2 c. Cheddar cheese, shredded
2 1/2 seasoned croutons (one 7 oz. pkg.)
2 lbs. sausage, browned and drained
4 eggs
2 1/2 c. milk
3/4 tsp. dry mustard
1 (4 oz.) can mushrooms, drained
1 c. cream of mushroom soup

Place croutons on bottom of a 9 x 12 inch greased pan. Top with cheese; add sausage. Beat eggs, milk, and mustard. Add mushrooms and soup. Pour over croutons. Refrigerate overnight. Bake, uncovered, at 300 degrees for 1 1/2 hours. Let set 5 minutes, then serve.