Brown sausage and 2 T. of chopped onion together until done.
Drain and set aside. Mix hash browns, remaining onions, seasoning salt, pepper,
and onion powder together. Place this mixture in a lightly greased 9x13
casserole dish.
Sprinkle cheese on top of potato mixture. Spoon sausage on top of cheese.
Top with mushrooms.
Mix together following and pour over casserole: the 5 beaten eggs, salt/pepper,
and milk.
Bake at 350 degrees for 45 minutes (or until done).