2 lbs. pork sausage
1/2 c. onion, chopped
2 1/2 c. croutons or stuffing
2 1/2 c. shredded Cheddar

Brown sausage and onions (drain). Butter 9 x 13 pan. Put croutons on bottom of pan, then layer sausage and then cheese.

Beat next 3 ingredients and pour over casserole. 2 1/2 c. milk 3/4 tsp. dry mustard

Refrigerate casserole overnight.

Before baking, mix topping and pour over top.

TOPPING:

1 can cream of mushroom soup
1/2 c. sour cream
1/2 c. milk

Bake at 300 degrees for 1 1/2 hours.