B.F.
I would say it's best to make it then freeze it. You can even cut it into serving and wrap and freeze.
Breakfast casserole:
1lb pork sausage (any kind you like)
8-10 eggs
2 Cups milk
2 slices bread, cubed
1 tsp dry mustard
1 tsp salt
1 Cup (4 oz) shredded Cheddar Cheese
Brown sausage, drain, mix together all other ingredients.
Spread sausage in 13x9" pan. (Spray pan with PAM) Pour remaining ingredients in pan. Refrigerate overnight. Bake in morning at 350 45 minutes or until lightly browned on top.
You can make for overnight or make and bake then.
I put some extra cheese on top a few sprinkles. Have had many like this casserole. I've never had any last to freeze later but I bet it freezes well.