Macaroni Casserole

1 cup celery, chopped
1 green pepper, chopped
1/4 tsp. garlic salt
salt and pepper to taste
1 can mushroom soup
1/2 cup milk
4 cups cooked macaroni
6 slices mild cheese

Saute celery and green pepper in a small amount of butter. Add mushroom soup, milk and seasoning; cook until it comes to a boil. Arrange layers of macaroni, cheese and soup mixture ending with cheese in a 1 1/2 quart casserole. Bake at 400 degrees for 25 minutes. Garnish with ripe olives.