Spread cubed bread in a greased 9 x 13 baking pan; top with sausage, onion, mushrooms and cheese. Combine remaining ingredients; whisk to blend. Pour mixture over top of casserole. Chill at least 1 hour. Bake, covered, at 400° for 40 minutes. Uncover, bake an additional 5-10 minutes. Makes 6-8 servings.