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

Right here, right now, I’m going to teach you how to make crispy sweet potato fries—despite the fact that they are not real fries. They are imposters, stand-ins, the understudies of the fry world, only to be eaten when a proper french fry is unavailable.
After years of testing (and disappointment), I’ve cracked the sweet potato code. Whether you deep fry them or bake them, these sweet potato fries will actually be crispy. Guaranteed.
But they'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.
Ingredients
- Sweet Potatoes
- Cornstarch
- Olive Oil




- Cut your sweet potatoes into fries. Let them soak in water.


2. Put a bit of cornstarch in a bag or bowl with a lid.
3. Shake the fries around in the cornstarch.


4. Lay the fries on a baking sheet.
5. Drizzle with olive oil.


6. Mix in the oil.
7. Separate fries on the pan and cook 'em.
10 years after posting this I'm still using the cheapest, most basic vegetable peeler around and it's pretty much every cook's favourite.
It's the Maybelline mascara of the vegetable peeling world. A reliable workhorse.
Table of Contents
Dipping Sauce

Meanwhile you can make the dipping sauce. Mix together ½ cup of mayonnaise with 1 teaspoon of Sriracha sauce and ¼ teaspoon of Cayenne Pepper.
You can adjust the proportions to taste. Mix it up and taste it then adjust as you like.
Saturated and Unsaturated Fats
Saturated Fats for frying
Would you like to save this stuff?
- Lard
- Tallow
Monounsaturated & Polyunsaturated Fats for frying
- Olive Oil
- Canola Oil
- Peanut Oil
- Sunflower Oil
You can use as much or any oil that you want.
(The more oil you use for oven baking the greater chance the fries will be crispy )
TIPS
- Cut the fries to about about ⅜ths of an inch. Bigger than that and they'll burn before they cook.
- 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.
- 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.
- 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 but ...
- Sweet Potato Fries will get dark fast because of their high sugar content. Don't forget to flip and turn them or they'll burn.

Deep Frying
Cut the fries, soak them in water for at least an hour and coat them with cornstarch as with the above recipe.
Instead of baking, pre-heat the fryer and fry until crispy.
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? I'm a french fry professional.

Ingredients
- 2 large sweet potatoes
- 1 Tablespoon of cornstarch
- *Dipping Sauce*
- ½ cup mayonnaise
- ¼ tsp. cayenne pepper
- 1 teaspoon or more Sriracha sauce
Instructions
- 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.
Notes
- 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.
Now that I've run you through all of this and convinced you it's the way to cook sweet potato fries, I'm going to try a new experiment with blanching the sweet potatoes in water and THEN baking or frying them. I will keep you updated.
Or as we say in the sweet potato world - I'll keep you in the loop regarding the sweet potato scoop.

Karena N Cawthon
Hi Karen,
Does this work with whole okra?
Karen
Hi Karena, I haven't tried it with Okra, but dusting almost anything with cornstarch like this helps it fry much better. ~ karen!
Dan
Ah, now I know what to do with those 2 sweet potatoes I never prepared for my Thanksgiving dinner that are sitting on my stove. Karen, we'd get along! :) I'm a doer too, so many projects, but I have so much to learn. Thanks for your blog! Yes, some projects take years to get right. I'm reminded of my learning how to make baklava, which is tricky. I eventually figure out how to make perfect baklava and then never made it again. Yes, I too obsess with health and, of course, baklava is just flour, honey and butter (a bit of salt, I guess), so NOT healthy food! But my banana bread cookies are to die for! Happy blogging!!!
Karen
THx! I definitely have NOT perfected bakalva. What with never having tried to make it, lol. But it would be a fun one to perfect and then - never make again. ;) ~ karen!
Lois
I really wish you lived next door so you could make these for me and deliver some. I really, really do.
Karen
LOL. Welllll I don't. But that does remind me that I could probably dig up my sweet potatoes today! ~ karen
Bettsi
Made these for lunch today. I've tried making oven fries many times with "meh" success. These were wonderful!!! The cornstarch is the key. Thank you so much- you really do know the art of doing stuff!
Karen
Thanks Bettsi! I'm glad they worked out well for you. There's a bit of a learning curve as I mentioned but it sounds like you got it right off the bat. ~ karen!
J
I purchased an air fryer and use it for cooking without oil and starch.
Dominique Nimmo Evans
Bonjour de Paris! merci pour cette bonne idée! my Stuart Scottish husband sent me your link hoping I’ll be interested ( he’s a gourmet gourmand!) and he won! anyway I love sweet potatoes and I’ll cook some your way very soon! have a nice day, it’s evening for us ……..🌻👍🍀❤️
Sara
I have such faith in your cooking skills. You always figure a way for things to work. I have a request: use an air fryer to cook real fried food and taste good. One of my daughters uses an air fryer to cook frozen stuff, but not room temperature food. You are smart, clever, and diligent. I know you can do it.
Karen
Hi Sara! I thought about investing in an air fryer once but decided that the amount of times I fry food, I WANT them to be fried. They just aren't worth the investment of money and more importantly kitchen space. So it might be an experiment I never get to I'm afraid. :/ ~ karen!
June
Air fryers are BRILLIANT! just like fried food without the fat so very healthy. You can add a tiny bit of oil to coat food. I NEVER fry food now - always use an air fryer!
Thanks for the recipe!
Mary Zimmerman
Karen:
OMGOSH! These were AMAZING! Even my son who hates sweet potatoes LOVED these! Thank you from the bottom of my heart! <3
Karen
So glad they worked for you Mary. And thanks for coming back and letting me know! ~ karen
Mary
These fries were OUTSTANDING! Thank you so much for the recipe! LOVED THEM and the Sriracha Mayo sauce! Even my son who hates sweet potatoes loved them!
Lavada
Since you’re revamping your entire site (which is marvelous, by the way), I thought you might be interested in a broken link.
Found here:
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.
Thanks for all you do. I have been a fan of yours for many, many years now.
Have a great day!
Lavada
sara
Is there a substitute for cornstarch ?
Karen
Hi Sara, I've never done it myself but you can try arrowroot powder. It *might* give you the same result. ~ karen!
Meg
I have always wanted to love sweet potato fries... but they always fell short. Using your technique and adding some salt free seasonings after the vegetable oil step... made these fries the BEST I have ever tried!! Thank you!!
plasterer bristol
Great recipe. Ours turned out great. Thanks for sharing. Simon