Guaranteed Crispy Sweet Potato Fries & Sriracha Mayo Dip

There are two ways to get guaranteed crispy sweet potato fries.  In your oven (yes!) or in a deep fryer. But even deep frying plain sweet potato fries won’t get them crispy. You need a tiny bit of the secret ingredient – cornstarch.

Skip right to the printable recipe.


Right here, right now I am going to teach you how to make crispy sweet potato fries. Even though they’re not a real french fry. They are french fry substitutes to be eaten when a real french fry can’t be found. 

Yes, I know.  But you loveeeeeeeee sweet potato french fries.  You like them wayyyyyyyyyy better than regular french fries.  That’s because you’re an amateur.   I on the other hand, am a french fry professional.

I have been making, eating and gorging myself on theses sticks of potato deliciousness for as long as I can remember.  In high school I ate so many of them at lunch that at the end of the year I threw up a ball of grease.  So … clearly … a professional here whose advice should be followed. 

But … if you’re on some sort of stupid meal plan, or you’re all out of regular potatoes, or you just feel like having something a little different than regular french fries, why wouldn’t you cook up some Sweet Potato French Fries?

Because they’re soggy messes.  That’s why. They’ll get brown but they don’t get crispy.

I’ve oven baked them, par boiled them and deep fried them and they don’t get crispy.  They get brown, but not crisp.

Finally, I’ve figured out how to make crispy sweet potato fries and the best part is you can do them in the deep fryer or the oven!  Either way, you’ll end up with crispy fries.  Guaranteed.

But like with most things, you’re more guaranteed if you do them in the deep fryer.

Here’s what you need to do to create this perfect sweet and spicy lunch or side dish.


Gather your sweet potatoes.


Get some corn starch.

Also get some olive oil. Just the cheap stuff.  Not the good stuff like my favourite Lorenzo No.5. Seriously best tasting olive oil ever.

Peel your sweet potatoes.  I have used the same brand of vegetable peeler for 15 years now.  It’s the cheapest, most basic vegetable peeler around and it’s pretty much every cook’s favourite.  It’s the Great Lash mascara of the vegetable peeling world.

Cut your sweet potatoes until they’re a medium thickness.  Not hugely thick cut and not shoestring.

Let potatoes soak in water for an hour – half the day.  (not mandatory, but recommended)

Preheat oven to 425°

Throw a Tablespoon or two of cornstarch into a plastic bag.

(update:  I’m reducing this to a definite 1 Tablespoon of cornstarch because people were reading this as 1 to 2 to 173 Tablespoons of cornstarch.  So it’s a hard 1 Tablespoon now.  Got it?)

Dump a handful of sweet potatoes into the bag with the cornstarch.  You don’t need to dry them with paper towels or anything.  Just drain the water and then give each handful you drop in the cornstarch a good shake.  Twist the top of the bag so it forms a balloon with some air inside and shake the fries around until they’re lightly coated with the cornstarch.  This is important.  Too much water and too much cornstarch and you’ll end up with a goopy mess.  Plus your fries will taste like cornstarch.

Put them on a non stick cookie sheet. The darker the cookie sheet the better – all the better to brown with.

Drizzle 2 Tbsps. of olive oil over the sweet potatoes. This is if you want to be healthy.

Any vegetable oil will work.  I’ve used sunflower, avocado, vegetable etc. etc. 

Saturated and Unsaturated Fats

Saturated Fats for frying

  • Lard
  • Tallow


Monounsaturated & Polyunsaturated Fats for frying

  • Olive Oil
  • Canola Oil
  • Peanut Oil
  • Sunflower Oil

You can use as much oil as you want.

(Update: The more oil you use the easier time you’ll have of getting the fries crispy but the less healthy they will be.)

I usually go the totally unhealthy route to make sure the fries are crispy. Just drizzle the oil across them and then mix them up with your hands to coat well.

Spread the whole mess out evenly on your baking sheet.

Arrange them so they have space between each fry.  The less of them on the pan the better they’ll cook.  Too many shoved together and they’ll never get crispy.  They’ll just steam.  So do NOT overcrowd the pan.  Pop the pan into your preheated oven and cook for 15 minutes.

Meanwhile you can make the dipping sauce.  Mix together 1/2 cup of mayonnaise with 1 teaspoon of Sriracha sauce and 1/4 teaspoon of Cayenne Pepper.

You can adjust the proportions to taste.  Mix it up and taste it then adjust as you like.

Check them after 15 minutes, flip them over (you might have to use a spatula depending on how “non stick” your pan is) and return to the oven if necessary for another 5 minutes.  The timing really depends on the size of your fry, the heat of your oven and how well your pan conducts heat.

(update:  You can see the pan I’m using here is very dark, this very dark, old, used pan cooks things faster and crispier. So if you have an old pan like this use it.  If you have a shiny, new baking sheet your fries will take much longer to cook, will have a greater tendency to stick and won’t get as crispy)


Yes. Guaranteed. Crispy. Sweet Potato Fries. There's one secret ingredient (corn starch, so not so secret) and a few tips and techniques that you have to follow. But if you do, it'll work and no more soggy sweet potato fries.

Maxwell Williams French Fry and dipping cup!!

If you prefer your food deep fried, (and who doesn’t) throw them in the deep fryer at the highest setting for a few minutes instead of sticking them in the oven. You STILL need to coat them in cornstarch.  Even in a deep fryer, sweet potatoes fries won’t want to get crispy unless they have a coating of cornstarch.

This is how I do them when I’m in a rush.  They’re always crispier than those from the oven, but far less healthy.

See? French fry professional.

Guaranteed Crispy Sweet Potato Fries & Sriracha Mayo Dip

4.5 from 6 votes
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Author: The Art of Doing Stuff


  • 2 large sweet potatoes
  • 1 Tablespoon of cornstarch
  • *Dipping Sauce*
  • 1/2 cup mayonnaise
  • 1/4 tsp. cayenne pepper
  • 1 tsp or more Sriracha sauce


  • Preheat oven to 425 or deep fryer to highest setting
  • Peel sweet potatoes, slice into medium thick slices (closer to thin than thick).
  • Soak potatoes at least 4 hours in water.
  • Drain water from sweet potatoes and shake dry with your hands.
  • Put 1 Tablespoon of cornstarch into food safe plastic bag.
  • Dump sweet potato fries into bag, blow some air into it, and shake bag until fries are coated.
  • Place fries on cookie sheet, drizzle with a couple Tablespoons of olive oil.
  • Toss fries until evenly coated with oil.
  • Arrange on cookie sheet(s) with lots of space in between fries to prevent steaming.
  • Cook in hot oven for 15 minutes then check.
  • The fries will release from the pan when they're ready to flip the same way a steak would.
  • Flip fries, and continue to cook for another 5-10 minutes.
  • (cooking time depends greatly on the quality of your baking sheet so keep an eye on them)
  • Dipping Sauce: Mix together mayo, pepper and Sriracha sauce. Adjust to your taste.


  • Do NOT use too much cornstarch. It will lead to heartache and raw, powdery tasting fries.
  • A dark, metal baking sheet will give the best results.
  • Sweet Potato Fries will get dark fast because of their high sugar content. Don't forget to flip and turn them.


  • Do NOT use too much cornstarch. It will lead to heartache and raw, powdery tasting fries.
  • A dark, metal baking sheet will give the best results.
  • Sweet Potato Fries will get dark fast because of their high sugar content. Don’t forget to flip and turn them.

Please note :  This recipe does have a bit of a learning curve.  It may take a few attempts to get your proportions of corn starch and oil correct.  It took me several years to figure out how to do this, but with these instructions it shouldn’t take you more than a couple of tries.  

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Guaranteed Crispy Sweet Potato Fries &  Sriracha Mayo Dip


  1. B.J.M says:

    Sound and look yummy! Great idea. Gonna give them a go! I always found the mushy thing disappointing in a sw.-potato-fry too. I was thinking of soaking the cut fries in ice water like is done for good regular fries…but this is definitely less time consuming.
    BTW – the cute dishes are no longer available and havent any ETA either. Whaaa.

    • Karen says:

      Brenda – Blech. That’s too bad. Also, I do soak my Sweet Potato fries in cold water before cooking them if I have time. I didn’t have too much time this particular day so they were only in the water for a hour or so. ~ karen

  2. Lynn says:

    I like my SP Fries dipped in lazy-gal aioli (Hellman’s/Best Foods mayonnaise with tons of minced garlic and a squeeze of lemon juice). Just about everything is good with garlic mayonnaise, though.

  3. Sarah P says:

    I have tried a wide range of (baked) sweet potato fry recipes and always end up with soft mushiness. Delicious, but mushy. I can’t wait to try your way!

    • Sarah P says:

      Hey, ALSO: do you think baking them on parchment paper on a baking sheet would change anything? I don’t have non-stick ones and I’m not big on scrubbing them clean.

      • Michelle Hill says:

        I use my silpat when I make oven fries. It works really well and is so much easier to clean than a pan or sheet. I think parchment would work, just keep an eye on it, as the oven is pretty darn hot for these fries.

    • Lalia says:

      I agree. They were the most delicious mush I’ve ever served. I had about 5 fries that miraculously didn’t stick.

  4. CourtneyOutLoud says:

    First – I love a woman who enjoys fried foods. Second, great tip about the corn starch!

  5. Liz S. says:

    I’ve redone my meal plan too. My son LOVES sweet potato fries. This will be a big treat for him. I’ve tried making them before and they were awful!

  6. Lisa says:

    This works with butternut squash too, although I think I used regular flour instead of cornstarch…maybe? But you have to cook them a little longer. I also may try this with those cool purple potatoes, because those made crappy fries the one time I tried. it.

  7. Bill Grigg says:

    And I just happen to have some sweet potatoes, sriracha mayo, some corn starch and even an oven on hand! Suh-weet!

  8. Sarah says:

    i do like sweet potato fries, but can we have a recipe on for reals french fries too??

  9. Michele says:

    OMG. This is just what I need. My boyfriend (who runs a BBQ joint in a bar) had declared all crispy sweet potato fries to be FAKE since he couldn’t figure out how to get them crispy. Can’t wait to show him this.

  10. Erin says:

    This is well timed! We tried to make SP fries on Friday night and like you said, they turned into a mushy mess. Take two will be coming soon, using your brilliant strategy!

  11. Joni Nawrocki says:

    Mmmm! Looks good! I’ve also read that coating them with egg white will give them that crisp texture. :)

  12. Sherry says:

    My hero! I make sweet potato french fries for lunch about 3 times a week. I am so excited to try this I can’t even tell you! How do you come up with this stuff??

  13. marilyn says:

    ok looked back and saw the temp posted sorry karen shoulda known you wouldn’t leave that out.

  14. marilyn says:

    karen i also have had that problem and fing that the temperature of the oven makes a difference as well, it has to be quite hot.

  15. brie says:

    yes yes yes!!!! accompanying the bbq tonight!!! :)

  16. Amie says:

    I bet you could use tapioca starch too!

  17. Angela says:

    So glad that I’m not the only one who chooses regular fries over SP fries. My hubby LOVES SP fries, so we buy the ones in the freezer section for him. I can’t always find ‘real’ sweet potatoes here (small town in Northern Japan) and the Japanese sweet potatoes are NOT as good as regular ones, so we may have to wait a while to try your recipe.

    p.s. For regular fries, sprinkle them with garlic salt, MMMMMMMMMMMMM MMMMMMMMM GOOOOOOD!

    • Nik says:

      Actually, I was gonna suggest garlic salt for SP fries… it’s actually a really neat combination, I think :) Oh– and coating a LOT of stuff with cornstarch solves the “crispiness (or lack thereof)” issue. I had eggplant fries just today, in fact :)

  18. Michelle says:

    I love the french fry tips! Thank you! But what I REALLY want to know: where did you get the cool french fry and matching dip bowls? LOVE THEM!!

  19. Jennifer says:

    Ah — corn starch?! Thanks for letting us in on your secret. Can’t wait to try — they look picture-perfectly delish. (Btw, your site’s loading much faster now. Whatever you did to tweak it worked.)

    • Karen says:

      Huh! I’m going to continue tweeking. I’m not sure what else to do! The quicker loading time also has to do w/ the number of pics. in a post and the time of day. Fingers crossed it gets even better. ~ karen

  20. Bev says:

    I have just done my meal plan for this week, so I will have to go back and re-jig it to try and fit in the SP fries… Man I really want some now!

    We get different sorts of SP or ‘Kumera’ in NZ, the orangey ones like you’ve used and yellow ones that seem less sweet. Can I use either?

    • Karen says:

      Hey Bev – I’ve never used the yellow ones but I can’t imagine it wouldn’t work. There’s no reason for it not to. Give it a shot and let us know! ~ karen

  21. sk says:

    mmm sriracha mayo…
    or anything with sriracha…

    the oatmeal says it best:

  22. Renee says:

    Hm, seems like I have already answered my own question. After some quick research, I found this sriracha sauce that has no MSG…
    “Roland Sriracha Chili Sauce”

    Anyone tried it?

  23. BCBev says:

    I bow down.

  24. fifi says:

    From one french fry lover to another – the very best french fries you will ever eat will be made in a chip truck under the Bluewater Bridge in Sarnia, ON. Just sayin…

    • Susan says:

      Nah, sorry, but Hutch’s on the beach in Hamilton couldn’t be beat. Course it was more than a few years ago that I was there…

      • Holly says:

        Gotta have Stan’s Fries in Brantford! ;)

      • Bill says:

        I love yam fries but from some of the comments i dont know if i should try these..aww what the hell the dog will i hope..and i was in Hamilton last week, i couldnt find Hutch’s Susan..seems it’s gone

    • Brianna says:

      Hey! Do you know the name of the chip truck under the Bluewater? Or what roads I take to get to it? I’m visiting Canada in a few weeks and could go for some good fries

    • Heather-Mae says:

      I’m from Sarnia (eons ago) and was thinking the same thing. :)

  25. Renee says:

    You are a genius. Just bought some sweet potatoes and will have to try this.

    Question: I like Sriracha sauce but I get migraines from MSG. I can usually handle a little bit (honestly, you don’t need much of the stuff), but was wondering… Does an acceptable alternative exist?

    • Karen says:

      Renee – There really isn’t anything around that tastes like genuine Rooster brand Sriracha sauce. It doesn’t contain MSG by the way, it contains Benzoic Acid. However, if you think you’ll still have a problem with it, you can try any hot sauce. Franks Red Hot, Melinda’s, even Tobasco. Like I said, Sriracha has a definite taste to it (delicious) but if you experiment with your own hot sauces I think you’ll be able to come up with something you like! Also I toned down the amount of Sriracha for this recipe to make it more compatible to the most amount of palates. I actually use around 2 teaspoons. ~ karen

      • Renee says:

        Thanks for the reply! I did find one online that has no MSG (I thought Rooster sauce did, glad to hear it may not) – posted link below. Hard to believe it will taste as good, though :)

        I’ll definitely use the heavier dose when I make this!

      • Kim says:

        I used regular hot sauce – Chaluha; twas tasty! the fries were a big hit at home.

      • Karen says:

        Kim – So you were able to get the proportion of corn starch to oil correct? ~ karen

    • KristenK says:

      You could probably use greek yogurt instead of the mayo too. Greek Yogurt and mashed avocados are my subs for mayo almost all the time.

      • Karen says:

        KristenK – Yes, I LOVE Greek yogourt. You’re right. I usually use it as a substitute for sour cream. ~ karen

      • Tara says:

        So, these were EPIC. By far the best sweet potato fry recipe I have tried. I did use use greek yogurt instead of mayo and it was tasty as well. I added dijon mustard, sriracha, and lemon. It could use some altering but the greek yogurt and sriracha was definitely a good starting point. Thanks for the recipe!

    • Jenni says:

      Sweet potato fries are also good with mayo mixed with curry powder and lemon juice. So if you are using 1/2 cup mayo use maybe 1/2 – 1 tsp curry powder and the same amount of lemon juice.

    • paul says:

      try some sambal olek.

    • Emma says:

      even better to eat with sweet potato fries is curry mayonnaise sauce. It’s mayonnaise mixed with curry powder and salt until it tastes yummy to you!

    • dave says:

      apple butter is also a great dip

    • Kevin says:

      I just made these and they were the strangest/weirdest fries I have ever had. I cooked them for 40 minutes and they still weren’t crispy. The corn starch was still like dry corn starch and the inside of the fries was just plain weird. Definitely won’t try these again!

      • Karen says:

        Well then Kevin, you did them wrong. I can tell right away you overpacked your baking pan (didn’t get crispy) and you didn’t use enough oil. So. There you have it. ~ karen

      • Kevin says:

        Actually they were no more packed on the pan than they are in your photo. And I used slightly more oil than you said to because I wanted to make sure there was some on each fry. Just didn’t work out well.

      • mary says:

        sounds like you didn’t use enough oil. or maybe your oven wasn’t hot enough (try an oven thermometer). either way, i made these tonight and they were amazing so the issue is definitely with you and not the recipe.

      • Heather says:

        Kevin I agree with you. The cornstarch was a very, very bad idea. I followed the recipe to a T and the fries were awful, I mean inedible awful. I will never make sweet potato fries this way again. The only reason I am posting a comment is so other people don’t waste their time, sorry:(

      • Karen says:

        Heather – You did something wrong. Sorry. But you did. If that weren’t the case then there wouldn’t be hundreds of comments stating how this recipe does work. I make it at least once a month and it works every time. To reiterate … sorry. ~ karen

      • Doris says:

        I tried these tonight and I have to say I’m in the failed camp. I soaked them in cold water for around 45 minutes. After 30 minutes on 450F, they still weren’t crispy. I practically dipped each one in oil. The bottom of each fry got a lot of colour (even black!) but the rest of the fry remained soggy and pasty. I’ve seen other recipes that use cornstarch as a coating to get that crisp (like calamari) which is why I was sure this would work but I don’t know it didn’t. I might try it again sometime though.

      • Karen says:

        Hi Doris – Did you turn the fries every 15 minutes? Also the oven temp. should be at 425, not 450. Maybe that was just a typo on your part. If all else fails, use the same technique but put them in a deep fryer. But I would bet with a couple of more tries you’ll get it all figured out. ~ karen!

      • Anon. says:

        People are reading your blog, therefore supporting you, and trying your recipes…. to immediately blame them for doing something wrong, as you sit all high and mighty is a little rude, and very untactful of you. Perhaps some manners in the new year.

      • Karen says:

        Dear person who refused to give their name or email address. Shove it. ~ karen!

      • Annie says:

        I had the same issue. Followed the recipe exactly used two cookie sheets to not crowd them and they were a soggy, soggy mess, the cornstarch probably works great if they are deep fried, but in the oven, they were inedible

      • Shelagh says:

        Dear Karen,
        I am so proud of you for telling Anon. to shove it! Just one more reason I follow your blog!
        I love sweet potato fries…especially baked in the oven with garlic infused olive oil and additive free salt…even if they are a bit soggy…so I will try these and keep playing until I get the proportions correct!

      • jdharm says:

        After reading the comments here I followed the instructions to the letter and got the same results as you. Everything appeared exactly like the posted pics except for the result. Suggested reasons:

        1) Natural gas oven vs Electric: one of the two major combustion products of natural gas is water vapor. If having fries just be close to each other is enough to keep them from getting crispy because of steam I can’t imagine putting them in a box with copious amounts of water vapor helps the situation…perhaps this only works best, or at all, in electric?

        2) Potato variety: I deep fried the failed bakers. Still limp. As an experiment I let some go till they started to turn black. Charcoal must be crispy, right? If not “crispy” then “brittle” at least. Nope, still limp. I managed to make limp charcoal. The only logic I can imagine behind this is the variety of potato just isn’t suitable for crisping because of its chemical make up?

        Just spitballin’ here.

      • Mj says:

        Just made these for my dad and I, and they turned out perfect.

        I don’t ever measure anything so I just dumped some corn starch in a bag, and also added cornflake crumbs and a little mrs.Dash for some extra texture. I soaked the fries for about 4 hours, drained them and let them sit for about half an hour before mixing them up. I placed enough for a large serving for two people on the cookie sheet and coated in oil. Baked at 425 for 15 min, flipped, baked for 15 minutes, then broiled for 3 minutes. There were a few that got a little too crunchy due to the different sizes. Overall they were GREAT and I will definitely make them again.

        I had a lot of sweet potatoes that I needed to use so I cut them all into fries. The ones that I did not season I threw in the freezer. Any tips on how to make these next time? Can I bake them frozen or should I let them thaw before coating them and baking? and do I need to soak them in water again?

      • Erica says:

        As someone who has tried these and failed to do it correctly, it seems that the amount of cornstarch is critical. Karen noted in the post that it may take some trial and error to get the amount right. I used far too much cornstarch and the raw flavor was not good. BUT, I can see the point and think with a bit of tweaking these will be really good. Lucky for me I have another sweet potato so I can try again tomorrow. Can’t wait to get it right!

      • Karen says:

        Erica – I’ve also had good luck with putting the cornstarch coated fries in a bowl and drizzling (glugging) oil over them and tossing them with my hands. Then I put them onto the baking sheet which I’ve also drizzled (gluggled) oil onto. ~ karen!

      • Annie says:

        Glugging oil over them sort of defeats the whole purpose of the oven rather than the deep fryer

      • Karen says:

        Not really Annie. It’s still less oil saturation than deep frying. If the fries didn’t work you’ve done something wrong. Seeing as I”m not there watching you I can’t say what it is exactly. Could be anything from a poor baking sheet (the darker the better) to not soaking your fries in water prior to cooking them. ~ karen

    • Scott says:

      So, you realize that means theres quite a few vegetables and fruits you cant eat, right? Seeing as how MSG was discovered because its a naturally occurring chemical in quite a lot of plants

      • Melissa says:

        Synthetically produced chemicals and refined naturally occurring compounds do not usually behave identically in the human body so your point is moot.

      • josh says:

        all of the MSG i have seen is fermented from corn. it’s not some wild, crazy synthetic chemical… it’s a “refined, naturally-occuring compound”, as you put it (grammatical corrections mine).

      • marianna says:

        Not to niggle, but she was right: you do not hyphenate compound modifiers that contain “ly” adverbs when used before the noun in the sentence. So “naturally occurring compound” is right.

    • Jeremiah says:

      Big sweet tater fry lover here. About the sauce though….I use a mixture of chili paste (the kind you find at a Vietnamese or Thai restaurant), and ketchup. It’s delicious!!

    • Christine says:

      Not sure if this has been mentioned yet, but if you get JetPuff marshmellow sauce and heat it for about 30sec-1min in the microwave it is FANTASTIC for sweet potato fries… thank sweet potato casserole!! This was an addiction for several months in high school and is a guilty pleasure now that im a little older :) Enjoy!

    • barb says:

      Do you dry the sweet potatoes after you soak them in water and before you coat them with cornstarch

      • Karen says:

        Barb – Just shake them vigorously so they aren’t soaking wet. No need to actually dry them with paper towels or dishtowels. ~ karen!

    • Lauren says:

      I’ve tried this a few times, and it seems for me, the trick for crispy fries is cooking them directly on a metal pan–no glass, no tin foil!

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