The trick that finally made my roasted sweet potatoes crispy!

London Lea holding a roasted sweet potato cube.

Turns out I’ve been settling for sub-par roasted sweet potatoes these last 10 years.

But just this last week I did something I’ve never done before. I added a little cornstarch to my go-to sweet potato seasoning blend (paprika, garlic powder, cumin and cinnamon), and ya’ll, I feel like I’ve been living a lie.

The edges came out so super crispy and crunchy (and without burning or browning too much!) and the middles stayed pillowy soft and absolutely perfect.

They were so good that I even spotted my self-proclaimed “sweet potato hater” ie, my hubby sneaking cubes right off of the tray before we sat down for dinner.

A few things that did it…

Here’s the part that took me a few tries to figure out: the oil goes on first, then the cornstarch and spices, and then the pan goes straight into the oven.

Let the seasoned cubes sit on the counter and the salt starts pulling water out, which turns the cornstarch gummy and slides it right off onto the pan.

If you’ve been here before and liked the original recipe, I have a feeling you’re going to love this one even more! (Recipe updated 9/12/26)

These Crispy Roasted Sweet Potato Cubes are plenty as a side on their own, but they’re also the base of my Sweet Potato Taco Bowls if you want to turn them into dinner.

Crispy roasted sweet potato cubes with caramelized edges piled on parchment paper.
Roasted sweet potato cubes are in a taco bowl.

Ingredients and Substitutions

For the exact measurements and detailed instructions, see the recipe card below.

Sweet potatoes, cornstarch, paprika, and garlic powder are the ingredients for crispy roasted sweet potato cubes.
  • Sweet potatoes. The star of the show! You’ll need about 2 pounds, peeled and diced. Any variety of sweet potatoes will work (jewel or garnet are my go-to!), so just grab whatever looks good at your grocery store.
  • Oil. Olive oil or avocado oil both work great here. Either one helps the potatoes caramelize and crisp up perfectly in the oven.
  • Cornstarch: This is the whole reason the edges come out crispy instead of soft. It goes in with the spices and pulls the surface moisture off the potatoes so they roast instead of steam.
  • Paprika, garlic powder, and cumin: This is my go-to sweet potato blend, and it’s what makes these taste like more than just roasted potatoes. I use sweet paprika, but smoked works too, and my homemade taco seasoning or chili seasoning can stand in for the whole blend if that’s easier.
  • Cinnamon: Just a pinch. It adds a warm, cozy depth without making them taste like dessert, so don’t skip it, but don’t go heavier either.
  • Fresh herbs. Totally optional, but a sprinkle of chopped parsley or cilantro adds a fresh pop of color and brightness right before serving.

Step-by-step Instructions

See the recipe card below for the full instructions, ingredient amounts, and a printable recipe.

Cut the sweet potatoes into cubes.

Peel the potatoes, then dice them into ¾-inch cubes. Try to keep them close to the same size so they roast at the same rate.

A sweet potato is peeled and cut into three-quarter-inch cubes on a wooden cutting board.

Toss with oil.

Add the diced potatoes to a large bowl and drizzle with olive or avocado oil. Give them a good toss until every piece looks glossy and evenly coated.

Pro Tip: The oil goes on before the cornstarch and spices. Coating them first is what keeps the seasoning mix from clumping up on you.

Cubed sweet potatoes are tossed with olive oil and the cornstarch seasoning blend in a glass bowl.

Mix the seasonings and sprinkle.

Whisk together the seasonings WITH the cornstarch so everything disperses evenly over the oiled cubes then spread out in a single layer on a parchment paper lined baking sheet. (And avoid aluminum foil since it tends to stick!)

Pro Tip: Don’t overcrowd the pan! If the cubes are touching or stacked, they’ll steam instead of roast and lose that golden crispiness.

Seasoned sweet potato cubes are spread in a single layer on a parchment-lined sheet pan.
Baker's half sheet pans.

The Sheet Pan I L❤️VE!

Your veggies will end up steaming instead of roasting if you overcrowd the pan. So my tip… use the largest sheet pan you have and spread everything out!

These are the sheet pans I use and love!

Get the PAN!

Roast in the oven and then dig in!

Bake at 400°F for 30-35 minutes, flipping after 20 minutes, until the edges are crispy and the middles are soft.

Pro Tip: Don’t let the seasoned cubes sit on the counter for long before going into the oven. The salt starts pulling water out within a few minutes, which turns the cornstarch gummy and slides it right off onto the pan.

Crispy roasted sweet potato cubes on a sheet pan after baking at 400 degrees.

FAQs

Why aren’t my sweet potatoes crispy?

Nine times out of ten it’s one of three things: you skipped the cornstarch, the pan was too crowded, or the seasoned cubes sat on the counter before they went in. Get them into a fully preheated 400°F oven right after tossing, and give them enough room that they aren’t touching.

Do I have to parboil them first?

Nope. A lot of crispy sweet potato recipes have you boil them first with baking soda, and it does work, but it’s a whole extra pot and about 20 more minutes. The cornstarch gets you the same crispy edges without any of that.

Do I have to peel the potatoes?

Nope! The skin actually adds extra texture and nutrients. If you like it, leave it on. Just give the potatoes a good scrub before cutting.

Can I roast sweet potatoes with other veggies?

Absolutely! Just make sure everything is cut to roughly the same size so it cooks evenly. Carrots, parsnips, and Brussels sprouts all roast beautifully with sweet potatoes.

How do I store leftovers?

Any leftovers can be kept in an airtight container in the fridge for up to 4–5 days. Pop them back in a 400°F oven or air fryer for about 5–10 minutes until hot and crispy again. The microwave works too (they just won’t be quite as crisp).

Tap stars to rate!

5 from 8 votes

Crispy Roasted Sweet Potato Cubes Recipe

By: London Lea
If your roasted sweet potatoes always come out a little soft and a little sad, the fix is one pantry ingredient. My go-to Crispy Roasted Sweet Potato Cubes get a spoonful of cornstarch mixed right into the seasoning blend, which gets the edges crispy and crunchy while the middles stay pillowy soft. Just 35 minutes and one pan is all you need!
Roasted sweet potato cubes with crispy edges are on a parchment paper lined baking sheet.
Yield 6 servings
Prep 10 minutes
Cook 35 minutes
Total 45 minutes
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Equipment

Ingredients 

  • 2 pounds sweet potatoes peeled and cut into ¾-inch cubes
  • 2 ½ tablespoons avocado oil or olive oile
  • 1 tablespoon cornstarch
  • 1 ½ teaspoons paprika sweet or smoked
  • 1 teaspoon garlic powder
  • ½ teaspoon ground cumin
  • ⅛ teaspoon ground cinnamon
  • 1 ¼ teaspoons salt
  • ½ teaspoon black pepper
  • Parsley or cilantro optional

Instructions 

  • Preheat the oven to 400°F and line a large baking sheet with parchment paper.
  • In a large bowl, toss the sweet potatoes with the olive oil until evenly coated. In a separate small bowl, mix together the cornstarch, paprika, garlic powder, cumin, cinnamon, salt, and black pepper. Sprinkle the seasoning mixture over the oiled potatoes and toss until evenly coated.
    2 pounds sweet potatoes, 2 ½ tablespoons avocado oil, 1 tablespoon cornstarch, 1 ½ teaspoons paprika, 1 teaspoon garlic powder, ½ teaspoon ground cumin, ⅛ teaspoon ground cinnamon, 1 ¼ teaspoons salt, ½ teaspoon black pepper
  • Spread the sweet potatoes onto the prepared baking sheet in an even layer and bake for 30-35 minutes, flipping after 20 minutes, until the potatoes are tender and crispy on the edges.
    2 pounds sweet potatoes
Last step! If you make this, please leave a review letting us know how it was!

Tap stars to rate!

5 from 8 votes

Video

Notes

Sweet potato cut: Cut the sweet potatoes into even ¾-inch cubes so they roast at the same rate. Give them room on the pan, since crowding steams them instead of charring the edges. Use two pans if you need to.
The cornstarch trick: Stirring the cornstarch into the seasonings and sprinkling it over the already-oiled potatoes is what gives them those crispy, caramelized edges instead of soft, steamy ones. Coating them with oil first, then the cornstarch-spice mix, keeps the coating from clumping.
The pinch of cinnamon: Just ⅛ teaspoon adds a warm, cozy depth to the sweet potatoes without making them taste like dessert. Don’t skip it, but don’t go heavier either.
Skins: If you like eating the skin, feel free to leave it on! Just scrub the potatoes well before dicing.
Storage: Store leftovers in an airtight container in the fridge up to 4-5 days. Reheat in the oven or air fryer for the crispiest texture.
Prep ahead: Peel and cube the sweet potatoes up to 2 days in advance and refrigerate. Toss with the oil and seasoning right before roasting so the cornstarch doesn’t turn gummy.

Nutrition

Calories: 180kcal, Carbohydrates: 26g, Protein: 2g, Fat: 7g, Saturated Fat: 1g, Sodium: 391mg, Potassium: 445mg, Fiber: 4g, Sugar: 5g, Vitamin A: 18770IU, Vitamin C: 3.1mg, Calcium: 41mg, Iron: 0.9mg

Nutrition information is automatically calculated, so should only be used as an approximation.

Made this recipe?Leave a comment below!

What to serve with it?

This recipe is a super versatile side dish, there are SO many ways to enjoy them!

Prefer them on the stovetop? My Skillet Brussel Sprouts and Sweet Potatoes cook the same cubes in one pan in about 30 minutes with no oven at all.

Or, dress them up in a salad with roasted beets.

Serve them with your favorite protein, like Air Fryer Boneless Chicken Thighs, Chicken Cordon Bleu, or Air Fryer Meatloaf.

Already have the cubes cut? Use them in my BBQ Chicken Sweet Potato Skillet, where they cook right in the pan with chicken and broccoli for a 30 minute dinner.

Wrap them up in a corn tortilla to make these Sweet Potato Black Bean Tacos.

Toss these cuties into a bowl full of other vegetables and quinoa like in this Sweet Potato Broccoli Quinoa Bowl or this Warm Fall Quinoa Salad!

Even More Delicious Sweet Potato Recipes

If you’re anything like me, one sweet potato recipe is never enough. Air fryer, hasselback, melting, or cut into fries, take your pick.

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5 from 8 votes

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Comments

  1. I bake sweet potato (yam) cubes with onion cubes garlic, s & p, nutmeg and allspice for a wonderful taste.
    Usually I make a space when they’re soft, and add an egg in each nest, continue baking until the eggs are just set. With a side dish of green veggies, this is my first choice meal.

    Reply

    1. Yay! So happy to hear you enjoyed the recipe! That sounds delicious. Thanks so much for taking the time to leave a comment!

      Reply

    1. Yay! So happy to hear you enjoyed the recipe, Julie! Thanks so much for taking the time to leave a comment!

      Reply

  5. 5 stars
    I haven’t really used sweet potatoes before but this was so simple and easy. I cooked them in the air fryer and they were perfect!

    Reply

  6. 5 stars
    This was excellent! Thanks so much for the post: Hate to have to admit it out loud, but it seems size does matter. Oy!

    Reply

  8. 5 stars
    this recipe was delicious! The only thing I did different was for the last 5 mins I turned on the broiler and let the potatoes get crispy!

    Reply

    1. Hi Theresa! I do not know the exact serving size but would estimate it to be about 3/4 to 1 cup of potatoes. Hope this helps!

      Reply

  10. Hi LB! My name is Rebecca and I’m the owner of Rebecca’s Gluten Free. My daughter Morgan was self-diagnosed 3 years ago when I was telling a close friend all of tge issues she was having. Well, summer came around and I figured it was tge perfect time to drop gluten from our diet. Not only did it help, but here I am 3 years later staeting my own gluten free business! I make gluten free cookie mixes. Not just plain old ordinary chocolate chio, but chocolate crinkle, lemon sugar, brownie, snicker doodle, pumpkin spice, and my husband’s favorite, coconut! I was wondering if with your permission I could send you some of my mixes to try. At this juncture of the business, I’m giving more away than actually selling. That’s alright though, I’m so confident in my product, I haven’t had a bad review yet! Oh and yes, more than just family and friends
    have tried them! Please feel free to go to my website rebeccasglutenfree.com and pick out a couple of mixes and I’ll get those shipped out right away. By tye way, if you love chocolate thennthe chocolate crinkle are the ones for you! Thank you!

    Reply

    1. Hi Rebecca! Thanks so much for such a generous offer. I’m really looking forward to trying your cookies out. 🙂

      Reply