These Roasted Sweet Potato Fries with Herbs, Salt & Pepper are an easy side dish made with sweet potatoes, olive oil, a light coating of cornstarch, garlic powder, fresh thyme, and cracked black pepper.

They roast up caramelized at the edges and tender inside, with a quick air fryer version too.

They’re a good fit for burger night, game day, or packing next to sandwiches for lunch.

You can keep them simple or set out a few dipping sauces.

If you’re putting together a fries-and-sides night, these are worth trying too:

Roasted Sweet Potato Fries with Herbs, Salt & Pepper

Ingredients You’ll Need

The cornstarch is optional, but it helps the fries brown instead of steaming. Fresh thyme gives the best flavor, though dried thyme or rosemary works fine if that’s what you have.

Ingredients

2 large sweet potatoes (about 1 1/2 lbs)
1 tablespoon cornstarch
2 tablespoons olive oil
3/4 teaspoon kosher salt, plus more to finish
1/2 teaspoon freshly cracked black pepper
1/2 teaspoon garlic powder
1 tablespoon fresh thyme leaves (or 1 teaspoon dried)
1 tablespoon chopped fresh parsley, for finishing

Directions

Heat the oven to 425°F and set a rack in the upper-middle position.
Line two large baking sheets with parchment paper.
Using two pans is the easiest way to keep the fries from crowding and steaming.
Peel the sweet potatoes if you like (I usually leave the skin on).
Cut them into 1/4- to 1/2-inch thick sticks, keeping them as even as you can.
Uneven fries cook unevenly, so the skinny ones burn while the thick ones stay soft.
Soak the cut fries in cold water for 30 minutes if you have time, then drain and dry them very well with a kitchen towel.
Soaking pulls out some surface starch, which helps the edges crisp.
Drying matters more than soaking, because wet fries steam instead of roast.
Toss the dry fries with the cornstarch in a large bowl until they’re lightly dusted with no white patches.
Drizzle in the olive oil and toss again until every fry is coated.
Add the salt, pepper, garlic powder, and thyme, then toss once more.
Spread the fries in a single layer across both baking sheets, leaving space between them.
Crowded fries trap steam and turn limp.
If they’re touching, grab a third pan.
Roast for 15 minutes, then flip the fries with a spatula and rotate the pans.
Roast another 10 to 15 minutes, until the edges are browned and caramelized.
Sweet potatoes go from golden to burnt quickly, so watch them closely near the end.
Air fryer option: Prepare and season the fries the same way.
Air fry at 380°F in a single layer for 12 to 16 minutes, shaking the basket every 5 minutes, until browned at the edges.
Work in batches so the basket isn’t more than half full.
Let the fries sit on the pan for 3 to 5 minutes.
They crisp up more as they cool slightly.
Finish with a pinch of salt and the chopped parsley.
Serve hot with your favorite dipping sauce and enjoy!

Air Fryer Version

Air fryer sweet potato fries come out crispier than oven fries and take about half the time. Prep and season them exactly the same way, including the cornstarch.

Cook at 380°F for 12 to 16 minutes in a single layer, shaking the basket every 5 minutes. Thinner fries finish closer to 12 minutes, so start checking early.

The catch is batch size (most baskets only fit one sweet potato’s worth at a time). Keep finished batches warm on a sheet pan in a 200°F oven while the rest cook.

Important Recipe Notes

Cut the fries evenly. Same-size sticks cook at the same rate. A mix of thick and thin means some burn before others soften.
Dry them completely. Any leftover water creates steam, and steam is the enemy of browned edges.
Don’t crowd the pan. Leave space between each fry on the sheet. Use two pans or cook in batches instead of piling them up.
Use the cornstarch. A light dusting helps the outside crisp. Toss it on before the oil so it coats evenly without clumping.

Expect softer fries than regular potatoes. Sweet potatoes have more sugar and moisture, so they caramelize more than they crunch. That’s normal.
Watch the last 5 minutes. The natural sugars burn fast at 425°F. Pull them when the edges are dark brown, not black.
Reheat in the air fryer or oven. Reheat at 400°F for 4 to 6 minutes. The microwave makes them soggy.
Season after cooking too. A final pinch of flaky salt and fresh herbs right out of the oven makes a big difference.

How to Serve, Store & Customize This Recipe

Serving:

Serve these right away while they’re hot and crisp. They go well with burgers, grilled chicken, or a sandwich. For dipping, try garlic aioli, chipotle mayo, or plain ketchup.

Storage:

Keep leftovers in an airtight container in the fridge for up to 4 days. They’ll lose their crispness, but a few minutes in a hot oven or air fryer brings them back. I don’t recommend freezing cooked fries, because they thaw soft.

Customization:

Add 1/2 teaspoon smoked paprika or chili powder for a smoky, spicy version. Swap the thyme for chopped rosemary, or toss with grated Parmesan right out of the oven.

For a sweet version, skip the garlic and pepper and use cinnamon with a pinch of sugar.