Preheat oven to 425°F and place empty baking sheet inside. This crucial step ensures fries hit a hot surface immediately, starting the crisping process right away.

Peel and cut sweet potatoes into uniform ¼-inch thick strips. Consistent sizing ensures even cooking—thicker pieces stay raw while thinner ones burn.

Soak cut fries in cold water for 30 minutes minimum. This removes excess starch, which is the key to preventing soggy fries and achieving crispy exteriors.

Drain and thoroughly dry fries using paper towels or clean kitchen towels. Any remaining moisture creates steam instead of crispiness, so pat them completely dry.

Toss with oil and seasonings in large bowl, adding cornstarch if using. Make sure every fry gets coated evenly for consistent browning and flavor.

Carefully remove hot baking sheet and spread fries in single layer without overcrowding. Space between fries allows air circulation, preventing steaming.

Bake for 25-30 minutes flipping halfway through at 15 minutes. Check for golden brown color and crispy edges before removing from oven.