Boil the macaroni according to the instructions on the box.
In the meanwhile prepare the sauce. Start by melting the butter in a casserole.
Add slowly while stirring the floor, salt and pepper.
Continue stirring and slowly pour in the milk. Continue stirring until the sauce start to get thicker.
Add in the cheese and stir until the cheese is melted.
Pour away the water from the macaroni and ad them in the cheese sauce and mix well.