Sausage Egg Bake

1 1/2 Cups milk
1 1/2 Cups sour cream
1 Can cream of mushroom soup
2 1/2 Cups croutons
2 1/2 Cups milk
2 1/2 Cups cheddar cheese, shredded
2 Cups onion
2 Pounds sausage
3/4 Teaspoon dry mustard
8 Eggs

Brown sausage and onions then drain. Spray 9� x 13� pan with oil. Spread croutons on the bottom. Add sausage and onions then spread cheese on top. Beat eggs, 1 1/2 cups milk, and dry mustard and pour over the top of sausage. Refrigerate overnight. Before baking in the morning, mix soup, sour cream, and milk and pour over the top of sausage mixture. Bake for 1 1/2 hours at 300�F degrees.