Boil water in a pot
Add macaroni and cook until tender
Drain the macaroni
Melt butter in the same pot
Stir in flour and cook briefly
Slowly whisk in milk
Cook until the sauce thickens
Add shredded cheese and stir until melted
Season with salt and pepper
Add the cooked macaroni to the cheese sauce
Stir until evenly coated
Serve warm