Combine first 3 ingredients in medium bowl. Stir in 1 cup cheese.
Cook macaroni as directed on package, omitting salt. Meanwhile, melt butter in large saucepan on low heat. Stir in flour and red pepper; cook and stir 2 min. or until bubbly. Gradually stir in milk; cook on medium heat 3 to 5 min. or until mixture comes to boil, stirring constantly. Stir in sour cream; simmer on low heat 3 to 5 min. or until thickened.
Add remaining cheese; cook and stir 2 min. or until melted.
Drain macaroni.
Add to sauce; stir to evenly coat. Spoon into 8 (1-cup) baking dishes sprayed with cooking spray; sprinkle with cheese mixture.