Preheat oven to 425°F. Grease a large baking sheet with cooking spray, or line with parchment paper.
Peel sweet potatoes and slice into 1/4-inch wide sticks.
Transfer chopped potatoes to a large bowl of cold water. Soak for 30-60 mins. Then, drain the water and put the potato sticks on a clean towel to dry.
Mix together cornstarch, garlic powder, paprika, and pepper in a small bowl. Set aside.
In a large bowl, mix sweet potatoes with olive oil. Then, add dry mixture and stir until potatoes are completely covered.
Transfer sweet potatoes to the baking sheet in an even layer. Use two baking sheets if needed.
Bake in the preheated oven for 15 min. Then, flip each sweet potato fries and bake for an additional 15 minutes or until crispy.
When the potatoes are ready, remove the baking sheet from the oven and sprinkle fries with salt or your favorite herbs.