3 gallons water
2 1/4 qts. elbow macaroni (2 lb. 10 oz.)
2 qts. reconstituted nonfat dry milk
1 c. butter, cut into sm. cubes (8 oz.)
1 tbsp. dry mustard
1/4 tsp. black or white pepper
1 gallon plus 2 3/4 qts. Process American cheese, shredded (3 lbs.)

Heat water to rolling boil. Slowly add macaroni. Stir constantly, until water boils again. Cook about 8 minutes or until tender; stir occasionally. DO NOT OVERCOOK. Drain well. Quickly stir milk into macaroni. Add butter and seasoning. Add the cheese and stir until the cheese is melted and the mixture is smooth. The mixture is quite liquid at this stage. Pour macaroni and cheese into serving pans.