In medium saucepan, melt butter over medium heat; stir in flour, and cook for 3-5 minutes stirring to form a roux; add salt and pepper; slowly add warmed milk, stirring well after each addition.
STEP 3
Cook and stir until bubbly.
STEP 4
Stir in cheese a small amount at a time until fully melted.
STEP 5
Drain macaroni; add to cheese sauce; stir to coat.