Cook macaroni according to package directions.
In medium saucepan, melt butter over medium heat.
Whisk in flour and cook for 3-5 minutes.
Add salt/pepper.
Slowly pour in milk and cook until bubbly.
Whisk in cheese a little at a time.
Drain the macaroni and add to the sauce.
Stir and serve.
(Add crispy, chopped bacon if desired!)