Preheat your oven to 425°F (220°C).
Wash and peel the potatoes. Cut them into wedges or cubes, about 1 inch thick.
Peel the onions and slice them into rings or half rings.
In a large mixing bowl, combine the potato wedges, onion slices, olive oil, garlic powder, smoked paprika, salt, and black pepper. Toss until everything is evenly coated.
Spread the potato and onion mixture evenly on a large baking sheet, ensuring that the pieces are in a single layer for even cooking.
Place the baking sheet in the preheated oven and bake for about 30 minutes, flipping the mixture halfway through, until the potatoes are golden brown and crispy.
Once cooked, remove from the oven and let cool for a couple of minutes.
Garnish with fresh parsley if desired, and serve warm.