To successfully oven-fry, you still need to use oil—just not as much as you’d need to fill a deep fryer. About 2 teaspoons of canola oil should be enough to coat one medium sweet potato cut into fries or wedges. Toss your oil and sweet potato pieces in a large bowl. Use your hands to mix them together to distribute the oil more effectively. This is also a good time to add seasoning, since the oil will help it stick evenly to the food. And while you’re at it, a little oil or cooking spray on your baking sheet is a good idea to prevent the fries from sticking. Cooking spray will give you the best coverage using the least amount oil.