1 1/2 lbs. pork sausage links
4 eggs, beaten
2 1/2 c. milk
1/4 tsp. dry mustard
3 c. plain croutons
2 1/2 c. (10 oz.) shredded cheddar cheese
1 (10 3/4 oz.) can cream of mushroom soup, undiluted
1 (2 1/2 oz.) jar sliced mushrooms, drained
2/3 c. milk

Cut each sausage link into 4 pieces. Cook until brown; drain and set aside. Combine next 3 ingredients. Layer croutons, cheese, sausage and egg mixture in a buttered 13"x9"x2" baking dish. Cover and chill overnight. Combine remaining ingredients; stir well and spread over top of casserole. Bake, uncovered at 300 degrees for 1 1/2 hours. 8 to 10 servings.