Parmesan Potatoes

1 package frozen hash brown potatoes

1 onion, chopped salt and pepper to taste

1/2 cup melted butter

1/2 cup Parmesan cheese

Preheat oven to 350. Butter a 9 x 13 pan. Add frozen potatoes, salt, pepper. Pour melted butter over the top, then the Parmesan cheese. Cover the dish with foil. Bake 45 minutes, then take off the foil; bake for another 45 min.