Cook pasta according to package instructions. Drain and set aside.
In a saucepan, heat ½ cup butter until melted.
Slowly whisk in flour until blended, and then slowly add in the milk. Bring mixture to a boil and continue stirring until it starts to thicken. Add in cheese, mustard, salt, and pepper until smooth.
Add macaroni to the sauce and stir until completely combined.
Serve topped with extra parmesan cheese and a sprinkle of pepper.
Notes
Feel free to add peas, chopped broccoli, or spinach to this recipe to add some fresh vegetables.