Preheat the oven to 450 degrees.
Scrub the sweet potato and cut into 1/2 inch slices (or thinner if you like your fries crispier).
In a bowl, toss the sweet potatoes with the olive oil, kosher salt, pepper, garlic powder, and cayenne.
Arrange fries evenly on a cookie sheet and bake for about 20 to 30 minutes minutes, checking after 20 minutes to prevent burning. Flip halfway so they cook evenly.