Preheat the oven to 400°F (200°C).

Prepare the potatoes: Wash and peel the potatoes, then cut them into wedges. Place them in a large bowl.

Season the potatoes and onions: Drizzle the olive oil over the potato wedges and onion rings. Sprinkle with garlic powder, paprika, dried thyme, salt, and black pepper. Toss everything together until evenly coated.

Arrange on a baking sheet: Spread the potatoes and onions out in a single layer on a baking sheet. Make sure the potatoes are not overlapping for even crisping.

Roast: Bake for 30-35 minutes, flipping the potatoes halfway through, until the potatoes are golden brown and crispy, and the onions are tender.

Serve: Garnish with fresh parsley, if desired. Serve hot.