3/4 cup diced green bell pepper 3 cups sliced celery 2 medium onions chopped 1/4 cup butter or margarine 3 cans condensed cream of mushroom soup (10 1/2 oz. each) 2 cups milk 12 ounces processed American cheese, cubed 24 ounces medium noodles 1 1/2 cup mayonnaise or salad dressing 1 can chopped pimientos (4 oz. size) 3 cans tuna, drained and flaked (9 1/2 oz. each) 1 cup toasted slivered almonds
Cook green pepper, celery, and onion in butter for 10 minutes. In Dutch oven or kettle blend soup and milk together; add onion mixture and heat through. Add cheese; heat and stir till cheese melts. Cook noodles in large amount of boiling salted water till just tender; drain. Combine drained noodles and 2 cups of the soup mixture. Toss to coat noodles Turn noodles into 18x12x2 1/2-inch pan or two 13x9x2-inchmetal baking pans. Combine remaining soup mixture, mayonnaise, pimiento, and tuna. Pour over noodles. Mix lightly. Sprinkle almonds over top.
Bake at 375° for 35 to 40 minutes. If chilled, allow an additional 15 minutes.