Preheat the oven to 450°F (230°C).
Cut the potatoes into 1/4 inch thick fries.
In a large bowl, mix together the cornstarch, flour, garlic powder, onion powder, paprika, salt, and black pepper.
Toss the fries in the mixture until they are evenly coated.
Drizzle the vegetable oil over the fries and toss again to make sure they are well coated.
Arrange the fries in a single layer on a baking sheet lined with parchment paper.
Bake for 25-30 minutes, flipping the fries over halfway through the cooking time, until they are golden brown and crispy.
Remove from the oven and serve immediately.