This restaurant-style hash brown casserole is loaded with cheesy onion flavor. Simple ingredients big taste. A perfect brunch recipe for those special occasions like Christmas morning.
Preheat oven to 425 degrees Fahrenheit. Spray 9 X 13 baking dish with oil so the casserole does not stick.
In a mixing bowl, add the thawed hash browns, olive oil, melted butter, salt and pepper. Gently mix to combine. Add this to the baking dish and spread out in an even layer.
Layer on the onions. Next layer the cheese on top of this; Parmesan, Cheddar, and Mozzarella.
Spray tin foil with the oil so the cheese does not stick. Cover the baking dish and bake for 30 minutes on the lower rack in the oven.
After 30 minutes, remove the foil and bake another 30minutes or until the cheese is golden on top and the potatoes are starting to crisp on the bottom.