Hash Brown Breakfast Casserole

This recipe is a nice change from the typical breakfast casserole.  The original recipe calls for sausage but substituted ham.  I think smoked sausage would be a nice substitute too.  You prepare this casserole the night before and bake it in the morning.  It makes ALOT so be prepared to share!  Here is the original recipe that we adapted this one from.

Hash Brown Breakfast Casserole

3 tablespoons butter
1 small yellow onion, chopped
4 cups frozen shredded hash browns, thawed
1lb bulk sausage, browned (we used diced ham)
2 1/4 cups milk
8 large eggs
1 teaspoon salt
1/4 teaspoon black pepper
2 tablespoons Dijon mustard
8 cups cubed French or Italian bread
2 cups (1/2 pound) grated Cheddar
2 cups (1/2 pound) grated Parmesan

Spray a deep 9x13 casserole dish with cooking spray.  Melt the butter in a large frying pan. Add the onion and saute over medium-low heat until soft, about 5 minutes.  In a large mixing bowl, combine the milk, eggs, salt, pepper, and mustard.  To assemble, spread bread cubes on the bottom of the dish and them top with the hash browns and onion.  Add sausage as the third layer. Pour the milk and egg mixture over these layers. Add Parmesan as the next layer and then the Cheddar.  Cover and refrigerate overnight.  Next morning, bake at 350 for 45-50 mins.