Place two racks in the center of the oven and preheat the oven to 425 degrees F.
In a large bowl combine the olive oil and minced garlic and heat in the microwave for 30 seconds. In a small bowl, combine the chili powder, garlic powder, thyme, cornstarch, grated parmesan, salt, and pepper. Toss the potato wedges in the oil mixture and make sure each piece is coated completely. Sprinkle the cornstarch mixture over the potatoes and using a large spoon or your hands combine everything. Alternately, you can add all the ingredients into a ziploc bag and shake. Place the potatoes in a single layer onto the prepared baking sheets.
