Lay bread out on counter to dry, approximately 1 hour. Break bread and spread in bottom of baking pan. Cook sausage and drain. Sprinkle sausage over bread.Shred cheese and sprinkle over sausage.
Beat together eggs, milk and mustard and pour over bread, sausage and cheese. Cover with aluminum foil and refrigerate overnight. Bake the following morning at 350 degrees for 30 to 45 minutes until eggs are set.