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Finger Food/ Potato/ Sides

Truly CRISPY Oven Baked Sweet Potato Fries

January 25, 2018 (Last Updated: May 23, 2022) by Chris Collins

How to get delicious and most importantly CRISPY Oven Baked Sweet Potato Fries. Follow this tried and tested 5 step method and you won’t be disappointed!

There seriously is nothing, and I mean NOTHING better than a batch of hot, sweet and salty, crispy sweet potato fries. There are so many great things the sweet potato brings us in life, but nothing greater than the classic fry. Having said that though, there really is nothing more disappointing in life than a batch of soggy sweet potato fries. Ugh, doesn’t the thought of it just make your heart sink? But unfortunately, it’s a far too common scenario, especially when making homemade sweet potato fries and more specifically, when baking them in the oven. It’s not easy! Getting crispy sweet potatoes using the oven is an art. But there is hope.

sweet potato fries in a small pot on chopping board with small white pot of dip

I have searched far and wide, and tested too many batches I care to even think about, in order to crack the code of getting crispy oven baked sweet potato fries every single time. Thankfully, I am here today to tell you that I’ve cracked it.

Look, I’m probably making it out to be a lot more difficult than it actually is, because once you try this method you’ll realise it’s a piece of cake. Could you just deep fry the bloomin’ things? Yes. But where’s the fun in that? Plus my waistline can’t deal with much more deep frying. So oven baked it is.

Are you ready for the crispy baked sweet potato fry challenge?


Crispy Baked Sweet Potato Fries – 5 Easy Steps

1. Size Matters

Grab yourself the largest sweet potato you can find, because they’re easier to handle. Peel and slice in half. From there you want to slice into about 1/4″ segments (photo below for guidance). The first mistake people make is making their fries too thick. It’s incredibly difficult to get crispy sweet potato wedges in the oven, it’s better to slice them too thin than too thick.

The second crucial step is to make sure they are all uniformly cut. Whether you’ve sliced them too thick, too thick or end up with pieces that look like shattered glass, at least make sure they’re all the same size so everything cooks at the same rate.

5 step by step photos showing how to cut sweet potato fries

2. Soak and dry

Do sweet potatoes need to be soaked before cooking?

In short – yes. Soak them in a bowl of cold water for at least 30mins. You can actually do this way in advance and pop in the fridge, the longer the better. Soaking your fries in water will pull out starch from the potato, resulting in a soft inside and a crispy outside. You’ll actually see all the starch at the bottom of the bowl after soaking them, which is strangely satisfying.

At the same time it is important that you dry the fries like you’ve never dried a fry before. Seriously, once they’ve had their bath we don’t want a spec of water left on them.

overhead shot of sweet potato fries soaking in glass bowl of water

3. The power of Cornflour!

Or cornstarch depending on what part of the world you’re from. Okay, so you’ve pulled the starch from the potato in order to get them soft, but you want the outside to be crispy, so you’ve gotta do some DIY. Cornstarch is perfect for this. A thin coating of cornstarch is key to get that crispy outside that you’re after.

Grab a large ziplock bag, place in your fries and a dusting of cornstarch. I find that 1 tbsp does the trick. Give it a really good shake to ensure a full even coating. You don’t want too much otherwise the fries will taste dusty, so pour out any excess cornstarch left at the bottom of the bag.

overhead shot of hand adding tbsp cornstarch to zip lock bag of sweet potato fries

Now it’s time for seasoning, and this really is up to your tastebuds. Spices that work well are chilli/chipotle powder, cumin, paprika, smoked paprika and cayenne pepper. I’ve also done a combo of rosemary and garlic before which came out nice!

HOWEVER, whatever you do, don’t add salt. One more time, do not add salt at this point. I’ve experimented by adding salt before and after the cooking process and adding it before they go in the oven seems to wilt the fries too much. Adding salt at the end drawers out that final bit of moisture without leaving them too wrinkly.

overhead shot of hand adding tbsp seasoning to zip lock bag of sweet potato fries

What’s the best oil for baking fries?

The key with oil is using one with a high smoking point. As tempting as it is to use olive oil you must resist! Some olive oils can have a smoking point as low as 320F/160C which is no good when we are cooking the fries at 430F/220C. Oils such as peanut oil, sunflower oil and avocado oil have much higher smoking points. Here is a great article on smoking points of oils.

overhead shot of hand adding tbsp oil to zip lock bag of sweet potato fries

4. The baking method – broken down

Why don’t my sweet potato fries get crispy?

A few crucial steps when baking the fries to avoid them turning soggy.

First things first, you want to either spray the tray with a light coating of oil, or use a good quality heavy duty foil or parchment paper so the fries don’t stick.

Secondly you want to make sure you don’t overcrowd the fries. As the fries cook they will release steam, if they are crowded together they are going to consequently steam instead of roast. These sweet potato fries are divas, give them space. Use two trays if you need to.

You want to cook them on a high heat, so as I mentioned earlier you’re looking at 430F/220C. Ironically you don’t want to bake these fries, you want to roast the heck out of them. Cooking on a low heat will bake them, leaving them soft and soggy. Because the fries are quite thin it’s not going to take long at all for the inside to cook, so a short(ish) sharp stint of high heat will focus on getting the outside crispy.

overhead shot of sweet potato fries on baking tray pre oven

How long to bake sweet potato fries?

After around 15mins you want to take them out, flip them over and put the trays back in the opposite way. This will ensure an even roast across the board.

From there on out it usually takes around another 10-15mins until they risk burning. You will find they go slightly black but with baked sweet potato fries unfortunately that’s inevitable.

overhead shot of sweet potato fries on baking tray post oven

5. The aftercare

Once cooked, the key is to turn off the heat and open the oven door. This step is crucial for crispiness. Strangely sweet potato fries become more crispy as they cool, so let them rest for a good 15 mins. After, it’s finally time for the salt to draw out that final bit of lingering moisture and allow the final ‘crisping’ phase.

When it comes to serving sweet potato fries, I love serving with Sriracha Mayo or BBQ Mayo, but check out my Delicious Dips for more inspo!

Well there we have it folks, it’s over to you. Are you ready for the crispy sweet potato fry challenge?

hand dunking single sweet potato fry into small white pot of sriracha mayo

How to make Truly Crispy Oven Baked Sweet Potato Fries (Full Recipe & Video)

Crispy Oven Baked Sweet Potato Fries

Truly CRISPY Oven Baked Sweet Potato Fries

How to get delicious and most importantly CRISPY Oven Baked Sweet Potato Fries. Follow this tried and tested 5 step method and you won't be disappointed!
4.50 from 8 votes
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Servings (click & slide): 4
Course: Appetizer / Side Dish
Cuisine: American
Prep Time: 15 minutes
Cook Time: 45 minutes
Total Time: 1 hour
Calories per serving: 265kcal

Equipment:

  • Large Greaseproof Baking Tray (use two if you need to)
  • Large Bowl (for soaking fries)
  • Large Zip Lock Bag (for coating fries)
  • Sharp Knife & Chopping Board
  • Potato Peeler
  • Clean Tea Towel
  • Spatula/Turner

Ingredients (check list):

  • 2lb / 1kg medium Sweet Potatoes, peeled (2lb/1kg total BEFORE peeled)
  • 2.5 tbsp Oil (with high smoking point e.g Avocado, Vegetable, Sunflower)
  • 1 tbsp Cornstarch/Cornflour
  • 1 tsp EACH: Chilli or Chipotle Powder, Paprika, Garlic Powder or seasoning of choice (see notes)
  • Salt, to taste

Instructions:

Preparing the Fries

  • Slice the sweet potatoes in half (vertically) then slice them into 1/4" strips. Cut those strips into fries approx 1/4" thick. 
  • Soak in a bowl of cold water for 30mins (or as long as you have time for). Thoroughly dry with a kitchen towel. This step is essential to remove as much moisture as possible.
  • Place in a large zip lock bag with cornstarch/cornflour. Zip the bag up and give it a mix around with your hands to completely and evenly coat the fries. Shake out excess cornstarch/cornflour.
  • Zip open then add 2.5 tbsp oil alongside your seasoning of choice. Give them another mix around and ensure they're evenly coated. Don't add salt at this point.

Cooking the Fries

  • Preheat oven to 430F/220C.
  • Evenly space out on a good greaseproof oven tray (or lightly sprayed with oil or lined with parchment paper - just so they don't stick to the tray). Spacing them out if important so they don't steam on each other.
  • Place in the oven for 15 mins. Take out, flip the fries and place the tray back in the other way to ensure an even bake. Cook for another 10-15mins or until just turning dark brown.

Aftercare

  • I find the fries crisp up as they cool slightly, so I like to turn off the oven, open the door slightly and leave for 10 or so mins (or until they begin to crisp). However, if they're already looking pretty crisp, just remove them from the oven and leave them for a couple of minutes.
  • Toss in a good pinch of salt, then serve up and enjoy!

Quick 1 min demo!

Notes:

a) Fresh Potatoes - Aim to get to get the freshest sweet potato you can find. Leave the soft one knocking about at the back of your cupboards for some mashed potatoes a different day.
b) Uniformed - When cutting your fries it's essential to get them all uniformed in size. It is also better to have them thinner rather than thicker.
c) Shake it off -  Once you've fully coated your fries with cornstarch, remove any excess that didn't stick. Leaving it there and mixing it in with the oil will create clumps that'll stick the fries and cause them to taste powdery.
d) Seasoning - I love a combo of 1 tsp chilli or chipotle powder, 1 tsp paprika and 1 tsp garlic powder. You can use you favourite seasoning, or just add salt at the end! If you're adding your own seasoning I wouldn't go above 3 tsp worth, otherwise the fries can come out dusty/grainy. Cumin, onion powder and smoked paprika also work nicely.
e) Timings - Unfortunately cooking times will differ slightly on the make of your oven, the size of fries you cut, the position of the fries on the tray etc etc. The ends of the fries are likely to turn slightly black, but just be vigilant throughout to ensure the whole fry doesn't burn.
f) Serving - I love serving with Sriracha Mayo or BBQ Mayo, but check out my Delicious Dips for more inspo!
g) Calories are based served between 4 people.
h) Technique inspiration came from layerofhappiness, cookieandkate, thecookful and foodiewithfamily

Your Private Notes:

Nutrition:

Nutrition Facts
Truly CRISPY Oven Baked Sweet Potato Fries
Amount Per Serving
Calories 265 Calories from Fat 64
% Daily Value*
Fat 7.11g11%
Saturated Fat 0.85g4%
Polyunsaturated Fat 0.976g
Monounsaturated Fat 4.941g
Sodium 125mg5%
Potassium 764mg22%
Carbohydrates 47.46g16%
Fiber 6.8g27%
Sugar 9.48g11%
Protein 3.57g7%
Vitamin A 32176IU644%
Vitamin C 5.4mg7%
Calcium 68mg7%
Iron 1.39mg8%
* Percent Daily Values are based on a 2000 calorie diet.
Nutrition is based on the absence of salt unless stated as a measurement in the ingredients. Cost is worked out based on ingredients bought from UK supermarkets, then divided by the number of servings. In both instances these values are just for guidance. Please check out my FAQ Page for more info.
Tried this recipe?Show me how you got on by tagging @dontgobaconmyheart_ on IG and #dontgobaconmyheart
Looking for more?You'll find plenty more delicious comfort food like this in my Debut Cookbook 'Comfy'

For more similar recipes check out these beauties:

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Recipe Rating




29 Comments

  • Reply
    Barbara
    June 17, 2023 at 2:11 pm

    5 stars
    This was quite the process to make some fries, but I was pleasantly surprised with how they turned out. Were they the crispiest sweet potato fries I’ve ever had? No. But they were pretty darn close, which is impressive given they were baked. Things I noticed for those who haven’t tried yet:

    1. The spacing between fries seemed to be most important. Those with the most space crisp up the best.
    2. A good greaseproof tray is a must. I had mine on two trays, one was brand new and worked like a charm. One was a little older and didn’t work quite as well (few stuck).
    3. Shorter fries were crispier than longer fries, so I recommend using small sweet potatoes.

    All in all a fun/tasty project. Will repeat now I know what to expect with the method.

    • Reply
      Chris Collins
      June 17, 2023 at 2:28 pm

      Great to hear these were a success, Barbara! Thanks for popping back for such a thorough review 🙂 C.

  • Reply
    Valerie
    January 6, 2023 at 1:49 am

    You totally broke the code on limp sweet potato ! Thank you it will be my only way to cook them from now on! Thanks so much. I think not salting before cooking made a huge difference.

    • Reply
      Chris Collins
      January 6, 2023 at 10:52 am

      Great to hear these went down well, Valerie! 🙂 C.

  • Reply
    Mary
    October 29, 2022 at 12:37 pm

    5 stars
    I was skeptical of trying this as I have had such awful luck with sweet potato fries in the past. I must say I was pleasantly surprised with how great they came out! Followed the recipe to a T (same seasoning). Keep a keen eye on them because they char quickly!! Mary.

    • Reply
      Chris Collins
      October 29, 2022 at 1:16 pm

      So great to hear, Mary! Thanks for popping back for a review 🙂 C.

  • Reply
    dmclyn
    May 22, 2022 at 10:26 pm

    1 star
    Sorry for the bad review, but I just made this recipe and followed the instructions carefully. The fries have stuck to the foil, and I find this to be so frustrating after all the prep work. Why not suggest oiling the foil first or using parchment paper?

    • Reply
      Chris Collins
      May 23, 2022 at 8:38 pm

      Sorry to hear this happened! I have personally never had this issue with a good quality heavy-duty foil, otherwise I’d have certainly suggested an alternative. I’ve updated the post and added parchment paper as a suggestion. I hope you get to try these again with better luck! C.

  • Reply
    DH
    March 7, 2021 at 4:58 pm

    Do you leave them in the oven with the door open for 15 minutes?

    • Reply
      Chris Collins
      March 8, 2021 at 7:00 pm

      The final stage is leaving the oven door ajar, yes 🙂

  • Reply
    Jo
    January 7, 2021 at 11:12 pm

    5 stars
    This is my go-to recipe for sweet potato fries. Easy and truly crispy, the fam loves ’em. Thanks!!

    • Reply
      Chris Collins
      January 8, 2021 at 10:17 am

      That’s awesome to hear, Jo! Thanks for the review 🙂

  • Reply
    Leslee
    November 6, 2019 at 12:18 pm

    I’m hoping to make a large quantity for about 12 people. Do you recommend two pans, bottom and top racks of oven and flip halfway during cooking?

    • Reply
      Chris Collins
      November 6, 2019 at 3:22 pm

      Yep thats should be fine!

      • Reply
        Leslee
        November 6, 2019 at 9:38 pm

        Great! Thanks so much. I’ll probably use convection bake at 400 degrees to keep the heat circulating all around.

  • Reply
    Sarah
    January 28, 2018 at 1:39 pm

    5 stars
    Looks delicious !

    • Reply
      Chris
      January 28, 2018 at 4:49 pm

      Thanks, Sarah! 🙂

  • Reply
    Tina
    January 26, 2018 at 3:33 am

    5 stars
    Your step-by-step pictures are very helpful, I lOVE this! I’m saving this recipe, for later, I haven’t quite mastered crispy sweet potato fries.

    • Reply
      Chris
      January 26, 2018 at 2:58 pm

      Thank you, Tina! I believe you’ll master them!!

  • Reply
    Michelle @ Vitamin Sunshine
    January 26, 2018 at 2:05 am

    5 stars
    What a great tutorial — love sweet potato fries, but I do always wish they were a little crispier! Pinning to remember to try this!

    • Reply
      Chris
      January 26, 2018 at 2:58 pm

      Thanks, Michelle! Let me know how you get on 🙂

  • Reply
    Liz @ I Heart Vegetables
    January 26, 2018 at 1:53 am

    5 stars
    I loooove sweet potato fries! It’s not always easy to get them crispy but your method sounds perfect!

    • Reply
      Chris
      January 26, 2018 at 2:57 pm

      Tis a little bit tricky! Hopefully this helps 🙂

  • Reply
    Calleigh
    January 26, 2018 at 1:31 am

    Oh yes! I can do this using the sweet yam that’s been sitting in our pantry. Thank you for the helpful tips.

    • Reply
      Chris
      January 26, 2018 at 2:57 pm

      Awesome! Enjoy! 🙂

  • Reply
    Rebecca
    January 26, 2018 at 12:03 am

    Sweet potatoes are so underrated!

    • Reply
      Chris
      January 26, 2018 at 12:08 am

      I so agree!

  • Reply
    Hilda
    January 25, 2018 at 10:29 pm

    This is very helpful. I will be giving this a try for sure. Thanks.

    • Reply
      Chris
      January 25, 2018 at 10:31 pm

      Oh fantastic! Enjoy!

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