At home mac and cheese recipe

INGREDIENTS 1 pound dried short pasta, such as macaroni 1 1/2 cups whole or 2% milk, divided 2 tablespoons all-purpose flour 2 to 3 cups shredded cheese, such as cheddar, Monterey Jack, or Colby 1 teaspoon salt 1/4 teaspoon powdered mustard Optional extras (cook before adding): ham, cooked ba