1Melt butter in a saucepan over medium heat; add flour. Cook 1 minute, stirring constantly with a wire whisk. Gradually add milk, stirring constantly.
2Bring to a boil; cook 1 minute, stirring constantly. Remove from heat; add cheeses and next 4 ingredients, stirring until cheeses melt. Combine cheese sauce and macaroni in a bowl; stir well. Serve immediately.