Preheat oven to 425 degrees Fahrenheit.
Line a baking sheet with aluminum foil and lightly coat the foil evenly with 1 teaspoon olive oil.
In a large Ziploc bag, place the sweet potato strips along with the 2 remaining teaspoons of oil, brown sugar salt, chili powder, and cayenne pepper powder (optional). Seal and shake the bag vigorously to coat the sweet potatoes evenly with the spices.
Pour the spiced sweet potato fries onto the foil-lined baking sheet and spread them out evenly.
Bake the fries for 30 to 40 minutes, until the fries have a crispness ot them. Flip the fries 2 to 3 times during the baking process for an even crunch.