One-Pan Easy Mac and Cheese

Developed September, 2018 from a recipe on America's Test Kitchen TV program on PBS. The method cooks the elbows in milk and water and adds the cheeses after the pasta is cooked al dente. American processed cheese includes 'emulsifying salts' — namely sodium citrate — that yield a smooth melt and prevent the sharp cheddar, there to boost flavor intensity, from oily separation.

2 c milk
3 c water
1 t salt
1 lb elbow macaroni
1/8 t cayenne
2 t Dijon mustard
8 oz American cheese, grated (from deli, not packaged slices)
8 oz sharp cheddar cheese, grated
8 oz sliced ripe tomatoes

Bring milk. water, and salt to a boil in a three-quart saucepan. Be careful to prevent boiling over. Stir in the macaroni, reduce heat to a fast simmer, and cook until pasta is tender and most of the liquid has been absorbed. Off heat, stir in the seasonings and the American cheese until melted. Return to heat and simmer gently 5 minutes. Off heat, stir in the cheddar cheese, top with tomato slices, and cover. Let stand 10 minutes to soften the tomatoes. Stir the tomatoes into the pasta, reheating as necessary. Variation: Replace the tomatoes with 1/2 cup frozen peas. Hint: Freeze the American cheese before grating.