Guaranteed Crispy Sweet Potato Fries & Sriracha Mayo Dip

There are two ways to get guaranteed crispy sweet potato fries. Even deep frying plain sweet potato fries won’t get you crispy fries. You need a tiny bit of the secret ingredient – cornstarch. Even oven baking sweet potato fries with a bit of cornstarch will get you crispy, delicious fries.

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 french fries for as long as I can remember.  In high school I ate so many french fries at lunch at the end of the year I threw up a ball of grease.  So … clearly … a professional here.

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. Sweet potato fries 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 …

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 your coated fries on a non stick cookie sheet.

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

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

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 ensure the fries are crispy. Just keep glugging the oil until the fries are well coated.

Using your hands, make sure the fries are well coated.

Arrange them on the sheet again, so they have space between each fry.  The less fries 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 fries 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 the fries 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 fries deep fried, 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 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

4.75 from 4 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. Megan Thompson says:

    Thankyouthankyouthankyou! I love sweet potato fries but I can never get the darn things crispy!

  2. Elayne says:

    These were amazing! Maybe I lucked out with the right proportion of cornstarch. I love sweet potato fries but since i don’t use a deep fryer they are always soggy. These were crispy and delicious. I heated a little oil in the bottom of the pan while the oven was warming up so I put them in hot oil and then drizzled a little bit more on top. The sauce was also really good, although I may have put a teensy bit too much hot sauce in….:)

  3. alsmouse says:

    I LOVE!! SP fries. I will be trying this very soon. For an extra yummy dip, try mixing plain youghert or sour cream with a healthy pour of REAL maple syrup. It elevates SP fries to perfection.

  4. Sarah says:

    Was Googling a “crispy sweet potato fries” recipe and found you! Can’t wait to try this tonight. But I must share my dip recipe with you: 1 heaping tablespoon of mayo, 2 heaping tablespoons of horseradish sauce (not plain horseradish, but the sauce you put on a roast beef sandwich) and 1 heaping teaspoon of brown mustard. Add about 1/4 teaspoon of dried dill & blend. (I never actually measure so this is my estimation and you might wish to readjust portions to taste) It is SUPER yummy for dipping sweet potato fries!

    • Karen says:

      Thanks Sarah! – My boyfriend will hate the sauce, and I will *love* it! He’s not much for horseradish or dill. I could eat the two of them as a meal. :) ~ karen

  5. Susie says:

    I noticed in your Nov. 16th response to Patrick you mention soaking them in water. I don’t see that mentioned in the original instructions. Am I missing something? Thanks!

    • Karen says:

      Susie – I’ve looked and looked and I can’t see my mention of soaking the fries in water first either! I don’t know if I accidentally erased it or not so I’ll have to add it back in. Yes, it’s best if you soak your fries after they’re cut for at least an hour, preferably half the day. Just cut them when you decide you’re making sweet potato fries and stick them in a bowl of water until they’re ready to use. ~ karen!

      • Karen N says:

        Are you supposed to blot them dry when you take them out of the water, before shaking them in the cornstarch? Any idea why they should be soaked? Thanks! Karen N.

  6. Kris says:

    Just made these. Mine turned out perfect! Thanks for the wonderful guidance!!

  7. Steph says:

    I have a ton of sweet potatoes in my fridge from my CSA share- now I have a new recipe to try! Thank!

  8. Great recipe – just tweeted about you! :)

  9. sawyer says:

    Tried these. AWESOME! So far it’s the best method I’ve come across.. although I just learned of another one where you toss them in beaten foamy egg white. I’m going to give that a go as well and see what happens. But your method was very tasty.

  10. Marg says:

    Pinterest follower, too! I am definitely going to try this. thanks!

  11. Trish says:

    I JUST had a major sweet potato fry fail last week. They came out totally limp and soggy. A total disappointment. But now I’m totally excited to try out your technique. I wish it was closer to the end of the day so I could get home and make these :)

  12. Patrick says:

    Thats a great idea! Sadly I made my first attempt before looking at your recipe and didn’t do the cornstarch coating part… I’m going to try it again tonight. Your sauce sounds delicious, I’ve been making a chipotle mayo, but i will have to give your sriracha mayo a try. Would i be correct in assuming if you are deep frying them, you can skip the oil coating? thanks!!

    • Karen says:

      Hi Patrick – You’re right. If you’re gonna deep fry, you don’t need to coat the fries in oil. You *do* need the cornstarch and you *do* need to soak them in water. Good luck! ~ karen

  13. Skinny Fat Kid says:

    This may be life changing…can’t wait to dive into that box of sweet potatoes I have on my counter!

  14. Holly says:

    Yep, used way too much cornstarch I think. Had to bake them for about 30 mins, and they still didn’t get that crispy (I even made sure to spread them out). They weren’t too bad, but after you ate one you would get this film on the top of your mouth (thanks to the cornstarch). It’s too bad because I did the exact ratio this recipe calls for. I’d say start with 1 tbsp MAX of corn starch for all your fries to lightly coat them. Looking forward to giving this another go sometime.

    • Karen says:

      Holly – Yes, I always have leftover cornstarch in the bag. It’ a matter of throwing a few in and quickly shaking them and removing them. Then again with the next handful. The problem is, if you don’t use extra cornstarch, you have trouble coating all the fries. Well … like I said, there’s a learning curve. :) Also, feel free to use more oil. Did you try the sauce? ~ karen

  15. Gabbi says:

    Best online sweet-potato recipe I found! Thank you so much for the share. I made it today and had a bit of a tough time figuring out at what degree to set the oven, maybe putting that and how many sweet potatoes per spoonful of olive oil would be a help for other first timers?

    • Karen says:

      Hi Gabbi – Sorry, you must have missed it. Right in between the pictures of the olive oil and the cut fries it says to preheat your oven to 425 degrees Fahrenheit. And yes, I’ll amend the recipe to say 2 Tbsps oil per pan of fries. It can be more … it just shouldn’t be less. Glad you managed to figure them out regardless! ~ karen

  16. Sandy says:

    Also found you via Pinterest. I looooove sweet potato fries, but usually buy the kind in a bag in the frozen section of the grocery store. I am so going to try this. BTW, I make my dipping sauce as follows: 4 tbsp. lite mayo, sriracha sauce (to taste) and some lime juice… delicious!!

  17. Natasha says:

    Mine didn’t turn out. I cooked them for 15 minutes and when I checked them they were soft and powdery, so I cooked them for a bit longer. Then they just got burnt and powdery. I am wondering if I did not put enough oil? When comparing my pictures to yours, it did not look like I put too much cornstarch.

    • Karen says:

      Probably not enough oil then, Natasha. You have to make sure the oil coats all the fries. Be vigilant about this. And if you’re having a hard time just use more oil! Easy as that. And as I always say, the fail proof method is cornstarch and then the deep fryer! ~ karen

  18. Lindsay says:

    Sorry – these looked delicious but were actually really gross :(

    • Karen says:

      Hi Lindsay – I’m guessing you did them wrong. Well … I’m not guessing, I know you did. Because they’re not gross in any way shape or form. You either a) used too much cornstarch or b) used too much cornstarch. As I said in the bottom of the post there’s a learning curve to them. To getting the ratios right. Also if you deep fry them there’s almost zero chance of screwing them up. ~ karen

  19. Averie @ Love Veggies and Yoga says:

    Found you on pinterest. These look awesome. And the dipping sauce is where it’s AT! :)


  20. Kimberley Preston` says:

    The cafeteria french fries and gravy WERE pretty tasty at Parkside. I *still* fondly remember them.

  21. Ashley says:

    ::Bowing down to the french fry queen.::
    I really enjoyed your candor and the tip is indispensable to me since I’m eating Paleo. Thanks!

  22. Jen says:

    Fantastic! Can’t wait to try this.

  23. Found you from Pinterest. Great recipe. I look forward to trying it.

  24. Caroline says:

    What is Sriracha sauce?

    • Karen says:

      Hi Caroline – Sriracha sauce is a hot sauce, kind of like Tobasco but a totally different flavour. It’s really good. It’s comes in a bottle about the size of an old, glass Heinz ketchup bottle and is usually in the Asian section or with the hot sauces. Now that you’re aware of it, you’ll probably notice it/be able to find it. :) ~ karen

  25. Jenifer says:

    This recipe sounds great, but what temp do you set the oven on? Thanks!

  26. Emma says:

    Hello Karen,
    I recently posted your recipe for crispy sweet potato fries. I received your comment and took it down immediately. I sincerely apologize, I meant no disrespect. My site is just a way for me to collect recipes for myself, and yours looked so delicious.

    I am very sorry.


  27. Elysse says:

    Mine just came out and they’re PERFECT!! At first I added way too much corn starch, but i used a colander to shake them around a bit and get some of it off…seemed to do the trick. Thanks so much for this post!

  28. Katy Vela says:

    OMG – just tried them – we have a professional fryer – HOT HOT OIL – 6 min – didnt have Sriracha but kinda made a hot mayo – maybe I CUT them too small – kinda like shoestring – BUT STILL EXCELLENT – I will do bigger cuts next time – but sooooo excellet

  29. Lori says:

    This is EXACTLY what I was craving for supper down to the Sriracha dip!! I’ll definitely be giving these a try tonight. Thanks!

  30. Rachel says:

    I a making these with dinner tomorrow and I can’t wait to see how they turn out.

  31. Amber E. says:

    Whoa. 1st attempt at the fries…WAYYYY too much corn starch! Oooops. Tried to get most of it off, didn’t really work, just resulted in a BIG BIG BIG mess in my kitchen. Sigh. Better luck next time?!!! They are in the oven right now…crossing my fingers they are still edible!

  32. Magic and Mayhem says:

    We made these tonight and tried to follow the recipe and all the comment suggestions exactly, but they were a pretty big flop. Even with a light coating of corn starch, the fries tasted powdery. They didn’t crisp up, despite the olive oil and additional cooking time. We had organic heirloom sweet potatoes from our CSA box and I’m kind of bummed to have wasted them.

    • Karen says:

      Magic and Mayhem – Eek. I’m sorry to hear you ruined your heirloom sweet potatoes. The only thing I can tell you is either your oven isn’t running hot enough, or you should just go straight to deep frying. There’s no way to mess them up that way. If you ever go to a restaurant with great sweet potato fries you’ll notice they’re always deep fried and they always have a light coating of cornstarch on them. Also … soaking them in water is important. Like I say … there’s a learning curve to these fries and the proportions of cornstarch and olive oil. If you give it another go let me know how they turn out. ~ karen!

  33. Lianne says:

    Oh, so sad “Caab Living is now in voluntary insolvency.”

    But now you have a collectors item!

  34. Lianne says:

    Sorry, only been following you since this summer…

    Used ‘Stumble!’ and found you remembered you from CityLine and have RSS’d (and now FB) you ever since! Love all your stuff and thanks for the link!

  35. Lianne says:

    Glad I’m not the only one who had soggy problems. Will try yours next time (I had given up).

    I’m surprised no one else has comments on your beautiful serving vessels… where did you get them?

  36. doodles says:

    I found your blog on these gems when poking around on Pinterest. I was intrigued. Because we were just at a favorite restaurant in town, husband loves their french fries come to find out they use CORNSTARCH!!!

    • Karen says:

      Doodles – It took me mannnnnyyyyyy attempts and experiments before I decided cornstarch was indeed the way to go with Sweet Potatoes. I’ll never go back! Glad you found the site! ~ karen

  37. We made them. . we loved them. . you are right, there is a learning curve. . go light light on cornstarch. . and for us we had to bake 20 minutes but we all loved them. . .thanks for sharing the details of how to make these. I just shared about these on my blog. . .I linked to here.

    Here is my post:

  38. found this on pinterest. . making them now. . will let you know how the family likes them. . thanks for sharing

    • Karen says:

      Su – I’m making them for dinner tonight! Sweet potato fries, tenderloin steaks and asparagus on the BBQ! I’m doing the deep fry w/ cornstarch route. Mainly I love them because of the dip. :) ~ karen

  39. Keith says:

    I just tried the oven baked wedge style SP fries. This was my third attempt. First I tried frying, no good. Second time I tried frying them bigger, again, no good. I will try you recipe Sunday.
    You are a Pro! I will post the results.

    • Karen says:

      Keith – Give it a go. Like I said it may take a couple of attempts to get a feeling for the proportions. If you want GUARANTEED results, use the cornstarch/deep fryer method. Perfect every time. ~ karen

  40. Elizabeth says:

    I love you for posting this.

  41. Ann says:

    The dip looks good but here in North Carolna the Sweet Potato State we sprinkle sweet potato frys with cinnamon sugar. You should try it. Looking forward to trying your crispy SP fries.

  42. Supal says:

    Thought I’d let you know that I added your picture with a link to this post on my blog under my “I’m craving” feature. Will be making these tomorrow!

    • Karen says:

      Thanks Supal! Like I tell everyone, there’s a bit of a learning curve with this. Light on the cornstarch and heavier on the oil. Guaranteed success the first time, use the deep fryer. (with the cornstarch) Good luck! ~ karen!

  43. You’re right about the learning curve on these. First time- undercooked sweet potato fries covered in oily starch.(yes I still ate them, I would eat anything with spicy mayo on it.) Second time- getting closer. I cooked them much longer, till they were browned. Some crispy, but very cornstarchy still, so I’ll chill out on the cornstarch next time. Hopefully that fixes it. I make sweet potato fries about once a week, so its worth figuring this one out.

    • Karen says:

      Jessica – Yes … go very light on the cornstarch. I add mine to the bag a large handful or two at a time. Makes it easier to get a light dusting. Also, as someone else pointed out, make sure your fries aren’t cut too thick. Good luck. Third time’s a charm. :) ~ karen

  44. Karen says:

    Duane – That’s true! You can’t have thick cut sweet potato fries! And also, like I say, if all else fails, do them with the cornstarch in the deep fryer or in a pan with oil! ~ karen

  45. Andy says:

    These rocked. This is the first time I made fries without them being soggy. The corn starch helped. Also, I put my sweet potatoes in cold water for 30 min and let them dry out a bit. This is supposed to help get rid of moisture. This was great.

  46. Katie says:

    Thank you! The world is a better place with sweet potato fries. Really, it is.

  47. Megan says:

    I love sweet potato fries more than regular fries so I’m so excited to try this out! I usually coat my sp fries with a mixture of spices (chili powder, cayenne, cinnamon, cumin, paprika, black pepper, thyme, and oregano) to give them a little kick. They taste delicious but are super mushy. I know I’ve been cutting them unevenly and too big and crowding my pan, so I’m going to fix those issues. Do you think it would interfere with the crisping process if I mixed the spices with the cornstarch? Or would you add the spices with the oil? Do them in a separate baggie? I just might have to make five batches and test all the options!

  48. Elisabeth says:

    Wow! Just made these alongside Carolina BBQ Turkey Burgers. What a healthy complement to a weeknight summer meal. The corstarch is like a magical ingredient!

    • Karen says:

      Elisabeth – Excellent! I’m glad they worked out for you. There’s a bit of a learning curve w/ them for sure. ~ karen!

  49. Kristy says:

    Ok… I DO love sweet potato fries dipped in home made Bleu cheese dressing…. However, as vile as Mickey D’s may be to adults, their ff dipped in a strawberry shake.. Well.. I think that takes professionalism to a whole other level, don’t you?! Lol
    (btw, please do not knock til you’ve tried it.. :))

  50. Paul says:

    these need to be fried – there’s no way they are getting crispy with corn starch, olive oil, and an oven – NO WAY. Fryer = crispy

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