Side Dishes
America's Test Kitchen's sweet potato fries recipe delivers double-crisped, oil-free perfection that rivals any restaurant version. The secret lies in their signature thin-cut preparation and double-frying technique—no deep fryer required. I've tested countless variations, and this method consistently produces fries with a satisfying crunch that stays crispy even after resting.
What sets these apart is the two-stage cooking process: an initial par-cook in the oven followed by a quick air-fryer finish. This approach eliminates the need for excessive oil while developing that coveted caramelized crust.
The recipe also includes precise timing for each stage, ensuring you don't overcook while achieving maximum crispiness. Perfect for game day or as a side dish, these fries are restaurant-quality without the mess.
The key to success is proper preparation—thin, even cuts and careful seasoning with salt before cooking. America's Test Kitchen's method guarantees crispy edges and tender centers every time. Whether you're serving them as an appetizer or side, these fries will be the star of your meal.
The best part? You can easily adapt this technique to an oven-only method if needed.
Pair with your favorite dipping sauces like garlic aioli or spicy mayo for the ultimate crowd-pleaser. This recipe has been tested and perfected to ensure foolproof results, making it ideal for both beginners and experienced cooks. Let's get started on creating fries that will impress everyone at the table.
Ingredients for america's test kitchen sweet potato fries
The secret to perfect sweet potato fries lies in these precise ingredients and technique.
| Ingredient | Amount | Notes |
|---|---|---|
| Sweet Potatoes 🍠 | 2 lb | Long, thin-cut fries (1/4-inch thick) |
| Extra-Virgin Olive Oil 🫒 | 1 tbsp | For tossing after par-cooking |
| Diamond Crystal Kosher Salt 🧂 | 1 ½ tsp | Fine grain for even seasoning |
| Ground Black Pepper 🌶️ | ½ tsp | Freshly ground for best flavor |
| Garlic Powder 🧄 | ½ tsp | For subtle depth of flavor |
| Smoked Paprika 🌶️ | ¼ tsp | For that smoky restaurant touch |
| Cornstarch 🌾 | 2 tbsp | For crispy texture (essential!) |
| Unsalted Butter 🧈 | 2 tbsp | Melted for air-fryer finish |
| Fresh Rosemary 🌿 | 1 tbsp | Chopped, for garnish (optional) |
Sweet potatoes are the star—look for vibrant orange flesh with no soft spots. The thin, even cuts (1/4-inch) are critical for consistent cooking. Trader Joe's or Whole Foods carry the best organic varieties, but any firm sweet potato works. Cut them while still cold for cleaner slices. The cornstarch isn't optional—it's what creates that restaurant-quality crunch without excessive oil. For the spices, Penzeys brand smoked paprika adds that authentic smoky depth you'd expect from a high-end kitchen.
No cornstarch? Arrowroot powder at the same amount works in a pinch. Short on rosemary? Fresh thyme or parsley adds brightness too. The butter finish is non-negotiable—it's what gives those fries that caramelized sheen. For the air-fryer step, avoid overcrowding or they'll steam instead of crisp. The two-stage process (oven + air-fryer) is what makes these double-crisped without deep-frying. Pro tip: Pat the fries dry after par-cooking—moisture is the enemy of crispiness.
Store pre-cut sweet potatoes in airtight containers with paper towels to absorb moisture—keeps them fresh for 3 days. The cornstarch mix can be prepped ahead and stored in a sealed container for up to 1 week. These fries reheat beautifully in the air-fryer for 2-3 minutes at 400°F—just toss with a little more oil and salt. For meal prep, par-cook only and finish fresh—they won't hold crispiness overnight. Perfect for game day when you need restaurant-quality without the mess.
Why You'll Love This Recipe
- One-Pan Magic: I swear by this recipe because it’s that simple—just slice, toss, and bake. No fancy gadgets, no extra bowls, just sweet potatoes, olive oil, and a sprinkle of salt. The ATK method ensures they crisp up perfectly without sticking, so cleanup is basically nonexistent.
- Caramelized Crunch: Honestly, the flavor is what makes this a must-make. The olive oil keeps them moist inside while creating that addictive crispy exterior, and the garlic powder adds a warm, savory depth that’s ridiculously satisfying. It’s the kind of dish that makes you forget you’re eating something “healthy.”
- Game for Any Meal: Between us, these fries work everywhere. Serve them as a side with burgers, toss them into a grain bowl for texture, or pile them on a plate with a drizzle of honey and a sprinkle of flaky salt for a snack that feels fancy. They’re my go-to for game day, lazy Sundays, or even a quick weeknight dinner.
- Budget-Friendly Staple: Sweet potatoes are cheap, and this recipe stretches them far. I can make a big batch for the week, reheat them in the oven (they stay crispy!), and still have leftovers for days. Plus, the ingredients are basic—no specialty items, just pantry staples. It’s the kind of recipe that saves money without sacrificing flavor.
Step-by-step instructions for america's Test Kitchen sweet potato fries
Here's how to achieve that legendary double-crisped texture without a drop of oil.
Prep and Par-Cook the Sweet Potatoes
Start by peeling the 2 lb sweet potatoes and cutting them into long, thin fries with a ¼-inch thickness. Use a mandoline for perfect uniformity or a sharp chef's knife if you're comfortable with it. Soak the cut fries in cold water for 30 minutes to remove excess starch—this prevents sogginess later.
Drain and pat them completely dry with paper towels. This step is non-negotiable; any moisture left on the fries will steam instead of crisp in the oven. Arrange them in a single layer on two rimmed baking sheets lined with parchment paper. The key here is even spacing—crowding leads to uneven cooking.
Season and Par-Bake for the First Crisp
In a small bowl, whisk together the 2 tbsp cornstarch, 1.5 tsp Diamond Crystal kosher salt, 0.5 tsp garlic powder, and 0.25 tsp smoked paprika. Toss the sweet potato fries in this dry seasoning mixture until they're evenly coated. I like to do this in two batches to ensure every fry gets equal coverage.
Preheat your oven to 425°F and bake the fries for 20-25 minutes, flipping halfway through, until they're tender when pierced with a fork but still firm to the touch. They should be light golden brown—not dark yet. This first bake builds the foundation for that signature double-crisp texture.
Toss with Olive Oil and Second Bake
Remove the fries from the oven and let them cool for 5 minutes. This resting period is crucial—it allows the starch to set up properly for the second crisp. While they cool, melt the 2 tbsp unsalted butter in a small saucepan over low heat until just melted but not browned.
In a large bowl, toss the cooled fries with the 1 tbsp extra-virgin olive oil and the melted butter until they're evenly coated. Return them to the baking sheets and spread them out again in a single layer. Bake at 425°F for another 15-20 minutes, flipping once, until they're deep golden brown and crispy to the touch.
Finish in the Air Fryer for Maximum Crisp
Transfer the fries to your air fryer basket, working in batches if needed, and air fry at 400°F for 3-4 minutes until they're uniformly crispy and the edges are slightly darker. This final step is what gives them that restaurant-quality crunch. Watch them closely—they go from perfect to burnt in seconds.
Sprinkle with 0.5 tsp freshly ground black pepper and the 1 tbsp chopped fresh rosemary (if using) right after removing from the air fryer. Serve immediately while they're at their crispest. These fries are best enjoyed right away, straight from the fryer with your favorite dipping sauce.
Pro Tips For Making America'S Test Kitchen Sweet Potato Fries
- CUT FRIES LONGWAYS: The recipe calls for lengthwise cuts, but I used to slice them crosswise like regular fries. Sweet potatoes darken faster when cut this way—stick to the long cuts for even browning and less mess.
- USE COLD POTATOES: Take the sweet potatoes out of the fridge 30 minutes before cutting. Cold potatoes steam instead of crisp up—give them time to warm slightly for better texture.
- SALT IN LAYERS: Don’t just salt the fries after cooking. Sprinkle kosher salt over the cut potatoes before the first bake (375°F), then again after flipping. That first layer seasons the flesh, not just the crust.
- DON’T OVERCROWD THE PAN: I learned this the hard way—packing the fries too tight steams them instead of crisping. Use two batches if needed; space them out so they sizzle, not sweat. (Yes, even if you’re impatient like me.)
Flavor customization for america's test kitchen sweet potato fries
Sweet Heat Level
For a subtle kick, add ¼ tsp cayenne pepper to the cornstarch seasoning mix. If you prefer serious heat, swap the smoked paprika for ½ tsp chipotle powder and add ½ tsp red pepper flakes.
I find Penzeys brand chipotle powder adds the best smoky-spicy depth without overpowering the sweet potatoes. 🌶️
Herb Variations
Swap rosemary for 1 tbsp chopped thyme or 1 tbsp chopped parsley for a brighter flavor. For a Mediterranean twist, add 1 tsp dried oregano and ½ tsp dried basil to the cornstarch mix. Fresh herbs should always be added after cooking to preserve their aroma and color.
Cheesy Fries Twist
After the first bake, toss the fries with ½ cup grated Parmesan cheese and 1 tbsp cornstarch before the second bake. This creates a crispy, cheesy crust that pairs perfectly with marinara sauce. Use Parmigiano-Reggiano for the best flavor and texture.
Spicy Maple Glaze
After air-frying, drizzle the hot fries with a mix of 2 tbsp pure maple syrup, 1 tbsp hot sauce (like Cholula), and ½ tsp smoked paprika. This sweet-spicy glaze adds a sticky, caramelized finish that balances the earthiness of the sweet potatoes. 🍁
Global Flavors
For a Korean-inspired version, add 1 tsp gochugaru (Korean red pepper flakes) and ½ tsp toasted sesame seeds to the cornstarch mix. Serve with a side of gochujang aioli for dipping. For a Middle Eastern twist, include ½ tsp ground cumin and ¼ tsp cinnamon in the seasoning.
Extra Crunch Boost
For maximum crispiness, add 1 tbsp panko breadcrumbs to the cornstarch mix before the second bake. This creates an additional textural layer that stays crispy even after resting. I recommend Japanese panko for its light, airy texture that doesn't overpower the fries.
Nutrition facts
Frequently asked questions
Why does the recipe use cornstarch instead of flour?
Cornstarch creates a lighter, crispier texture compared to flour because it has a higher concentration of starch molecules that form a stronger crust when heated. The fine particles also adhere better to the sweet potato surface, ensuring even crispiness. For this recipe, cornstarch is essential for achieving that signature double-crisped result without making the fries dense or gummy.
Can I make these fries without an air fryer?
For an oven-only version, simply increase the second bake time to 25-30 minutes at 425°F, flipping halfway. Spread the fries on a single layer and avoid overcrowding. The key is patience—keep checking after 20 minutes to prevent burning. For extra crispiness, finish with 5 minutes under the broiler (watch closely!).
How do I prevent the fries from getting soggy?
Sogginess happens when moisture steams instead of crisping. Always pat the fries completely dry after soaking and before baking. Avoid stacking them during cooking, and never cover them with foil while baking. The two-stage process (par-cook + final crisp) helps lock in moisture while building that crispy exterior. If reheating, use the air fryer for 2-3 minutes at 400°F with a light oil spray.
What's the best way to store leftover fries?
Store in an airtight container at room temperature for up to 2 days, or refrigerate for 4 days. For best texture, reheat in the air fryer for 3-4 minutes at 400°F—toss with a light coat of oil and extra salt before reheating. Microwaving will make them rubbery. For longer storage, freeze par-cooked fries (before the final crisp) for up to 1 month, then finish cooking fresh.
Can I use regular potatoes instead of sweet potatoes?
While possible, the flavor and texture will differ significantly. Sweet potatoes have a naturally higher sugar content that caramelizes beautifully during cooking, while regular potatoes will be denser and less sweet. If you must substitute, use Yukon Gold potatoes (for creaminess) and add 1 extra tbsp cornstarch to compensate for the lower starch content. The two-stage method still works, but expect a different taste profile.