|Prep time: 15 minutes||Cooking time: 1 hour||Total time: 1 1⁄4 hours|
1. Preheat oven to 375 degrees F (190 degrees C). Lightly grease a 9x9 or 8x8 inch baking dish.
2. In a large bowl, mix hash browns, mushrooms, cream of potato soup, sour cream, and Cheddar cheese. Spread evenly into prepared dish. Sprinkle with Parmesan cheese.
3. Bake 1 hour in the preheated oven, or until bubbly and lightly brown. Serve immediately.