1.  Wash and peel the sweet potatoes. 
2.  Cut them into evenly sized sticks, approximately ¼–½ inch thick. 
3.  Soak the sweet potato sticks in cold water for 30–60 minutes. 
4.  Drain thoroughly and pat completely dry with kitchen towels. 
5.  Place the sweet potatoes in a large bowl. 
6.  Sprinkle the cornstarch over them and toss until lightly coated. 
7.  Add the vegetable oil, paprika, garlic powder, black pepper, salt, onion powder, and chili powder if using. 
8.  Toss gently until the fries are evenly seasoned. 

Oven-Baked Method

1.  Preheat the oven to 425°F (220°C). 
2.  Arrange the fries in a single layer on a parchment-lined baking sheet, leaving space between them. 
3.  Bake for 20 minutes. 
4.  Carefully flip the fries. 
5.  Continue baking for another 15–20 minutes, until golden and crisp around the edges. 
6.  Allow them to rest for a few minutes before serving. 

Deep-Fried Method

1.  Heat vegetable oil to 350°F (175°C). 
2.  Fry the sweet potato fries in small batches for 3–5 minutes, until golden and tender. 
3.  Remove and drain on a wire rack or paper towels. 
4.  Season lightly with additional salt while hot. 
5.  Serve warm with your favorite dipping sauce.