12 slices bread, cubed with crust
3/4 to 1 lb. cheese, cubed (1/2 Velveeta & 1/2 cheddar)
1/4 c. melted butter
8 beaten eggs
2 1/2 c. milk
1 1/2 tsp. salt
1 1/2 tsp. dry mustard

OPTIONAL:

1 (10 oz.) can cream of mushroom soup
1 c. sour cream
1 (4 oz.) can mushrooms

Butter a 9 x 12 x 2 inch casserole dish. Layer bread then cheese in about 4 layers. Mix eggs, milk, salt and mustard. Pour over bread and cheese. Refrigerate overnight. Melt 1/4 cup butter and pour over the top of casserole. Place dish in a pan of water and bake at 325 degrees for 45 to 60 minutes. If desired, before baking, top with the optionals.