1. Boil 3 cups of water and add your pasta. Cook until about half the water remains. Then add milk, salt, pepper,and Dijon mustard. Lower your heat to medium so you don't scald the milk and make it curdle and cook until reduced down a bit, stirring occasionally.
2. Add your cheeses and cook until thickened about a couple of minutes, stirring constantly to keep the cheese from sticking.
3. At this point, you can add buttered breadcrumbs on top and put into the oven or serve hot the way it is.