Cut the potatoes into wedges 1/4 to 1/2 inch wide and soak them in cold water for 5 minutes. Drain the water and pat them dry with a paper towel. Then toss them with oil, salt, pepper, garlic powder.
Spread them out on a parchment paper-lined baking sheet.
Bake until brown and crisp on the bottom side, about 15 minutes, then flip and cook until the other side is crisp, about 10 minutes. Season generously with salt and pepper to your desired taste. Serve with ketchup.