Start by preheating your oven to 425°F. Place the potatoes in a large pot and cover them with water. Bring to a boil and cook until tender when pierced with a fork, approximately 15 minutes. Drain well. Prepare a baking sheet by coating it with 1 tablespoon of olive oil.

Carefully move the hot potatoes onto the prepared baking sheet using tongs. Smash each potato with the back of a heavy cup until they're about ¼ inch thick.

Drizzle the remaining olive oil and melted butter over the smashed potatoes. Season with kosher salt, garlic powder, and black pepper. Add a sprinkle of chopped parsley.

Roast in the preheated oven for 30 minutes, or until the edges are crisp and golden. After removing from the oven, sprinkle the Parmesan cheese over the potatoes. Return to the oven for an additional 5 minutes, or until the cheese is melted and bubbly.

Take the potatoes out of the oven and garnish with the remaining chopped parsley. Serve warm and enjoy!