1In 3-quart saucepan, cook and drain macaroni as directed on package. Return to saucepan; cover to keep warm.
2Meanwhile, heat oven to 350°F. Spray 8-inch square (2-quart) glass baking dish with cooking spray. In 2-quart saucepan, stir milk, flour, mustard, salt, black pepper and red pepper with wire whisk until smooth. Cook over medium heat, stirring constantly, until mixture boils and thickens. Remove from heat. Stir in cheese until melted.
3Add cheese sauce to cooked macaroni; mix well. Spoon into baking dish.
4Bake 20 to 25 minutes or until edges are bubbly.