Add the water, milk, bay leaf, salt, and pepper to a heavy-bottomed pot. Bring to a boil over high heat. Stir in macaroni and turn heat to medium-low. Continue cooking, stirring occasionally, until the macaroni is cooked to your liking, about 10 minutes (or according to package directions) for al dente.
Add in the mustard, onion powder, and American cheese. Cook, stirring constantly, for about 1 minute or until the cheese is completely melted. Remove the pot from the heat and add in the cheddar cheese. Mix well (the cheese doesn't need to be completely melted). Cover the pot and let stand for 3 minutes.
Meanwhile, turn your oven's broiler to high. Toss the cubed chicken or turkey with 1/2 cup of the Buffalo Sauce. Remove the lid from the pot and stir the meat mixture into the macaroni. Drizzle the top with the remaining wing sauce and sprinkle with blue cheese crumbles. Set under the broiler (6–7" away from the element), leaving the oven door cracked, until the cheese is softened, rotating once. Remove the bay leaf and serve.