Place the potatoes, onion, and red pepper on a large baking sheet. Drizzle with olive oil and toss until vegetables are well coated.
In a small bowl, combine garlic powder, salt, and paprika. Sprinkle the seasonings over the vegetables and toss again until well coated. Season with freshly ground black pepper, to taste.
Place the pan in the preheated oven and roast until potatoes are crispy, about 45 minutes.