If you are using your oven, preheat to 400 degrees. Wash and scrub your sweet potato and slice into thin strips. Place the sweet potato fries in a bowl.
Toss the sweet potato fries with oil and sprinkle in cornstarch or arrowroot powder and make sure the fries are evenly coated.
Place in your air fryer for 18 minutes, check halfway to make sure the sweet potato fries are cooking evenly. Your air fryer may require a shake. If you are using your oven bake for 20-25 minutes. Again, check-in and flip the fries so they are cooking evenly. More time may be needed to achieve the desired crispiness.
Once your sweet potato fries are golden brown and crispy remove from the oven/air fryer and place them on a plate. Sprinkle with red chili powder and salt. Enjoy.