CHICKEN SANDWICH CASSEROLE

12 slices bread (with crusts removed-optional)
1/2 stick soft butter
2 to 3 teaspoons prepared mustard
2 cups chopped cooked chicken
1 1/2 cups shredded cheddar cheese
1/3 cup finely chopped onion
1/2 teaspoon salt
1/4 teaspoon pepper
1 can cream of chicken soup

Preheat oven to 350 degrees F. Blend butter and mustard and
spread on bread. Lay six slices butter side up in casserole
dish. Combine chicken, cheese, onion, salt and pepper. Spread
over bread in dish. Cut remaining bread in half diagonally and
place over mixture in casserole. Pour soup over top. Bake 25 to
30 minutes.