Preheat your oven to 425°F.
Wash (or peel) the sweet potatoes and cut them into even, bite-sized pieces.
Place the cut sweet potatoes in a large bowl, sprinkle the cornstarch over them, and toss until they're evenly coated.
Add oil and seasoning to the sweet potatoes.
Spread the coated sweet potatoes in a single layer on a baking sheet lined with parchment paper.
Roast for 25 to 30 minutes, flipping halfway through to ensure even browning.
