Hash Brown, Broccoli, Sausage and Egg Breakfast Casserole

regular pork sausage

medium onion, finely chopped

and 1/2 cups cheddar cheese, shredded

mozzarella cheese, shredded

broccoli florets (steamed or cooked and drained)

hash browns (frozen, raw, uncooked, completely defrosted)

eggs

heavy cream

black pepper

butter, melted