Whisk in 1/2 tsp. salt, 1/4 tsp. black pepper, 1 cup shredded extra-sharp Cheddar cheese, and, if desired, 1/4 tsp. red pepper until smooth; stir in 1/2 (16-oz.) package elbow macaroni pasta. Spoon pasta mixture into a lightly greased 2-qt. baking dish; top with extra-sharp Cheddar cheese. Bake at 400° for 20 minutes or until golden and bubbly.