Preheat: Set your oven to 425° F (220° C) and line two large baking sheets with parchment paper.
Cut: Slice the sweet potatoes into even ¼-inch sticks.
Dry: Pat the potato sticks very dry with a clean kitchen towel or paper towel.
Toss: Place the fries in a large bowl and toss with the cornstarch until completely coated. Pour off any excess powder, then toss the fries in your oil and seasonings.
Space them out: Arrange the fries on the baking sheets in a single layer.
Bake & Flip: Bake for 15 minutes, then remove, flip the fries over with a spatula, and rotate the baking sheets. Return to the oven for another 10–15 minutes until browned and crisp.
Serve: Let them cool for 5 minutes before eating to allow them to crisp up further.