What I had for dinner:
Before I start, I must say that I don't really know American macaroni & cheese. I've had a version that is said to be superb, at Charles's Southern Kitchen, but I think that to wax properly poetic about it one has to have grown up in front of "I love Lucy" (or "Ozzie and Harriet" as Vin Scelsa just reminded me.)
Anyway, here goes "Macaroni au Gratin":
You'll need two saucepans and an oven-going dish (disposable aluminum, glass, etc).
Preheat the oven to 400F.
In the larger saucepan, bring plenty of water to a boil, and add 1/2 lb of macaroni (I use penne, but any round pasta will do). Cook at a moderate boil, with occasional stirring, until the pasta is just barely done. Typically a bit under the lower limit of the time on the package. Drain in a colander, toss in the oven dish with a little oil or butter to prevent sticking, and set aside.
In the same saucepan, place 1 pint of milk and a generous pinch of nutmeg (freshly grated is best) and bring carefully to a boil. Moderate heat and ceaseless vigilance or it *will* boil over.
In the other saucepan melt 1/2 stick of butter, add 1 chopped onion, and cook until soft. Stir once in a while, and keep looking at that milk! Add chopped garlic (I used 4 cloves), cook 30 seconds, and add all at once 1/4 cup of plain flour. Stir well with a wooden spoon and cook several minutes. The mixture is very thick, and must be moved around so that it does not stick. And keep looking at that milk!
Cool the butter/flour pan by placing it in a sink with cold water. When the milk boils, add it all at once to the other saucepan, place it back on the stove, and cook while stirring until the mixture is well blended. Salt and pepper to taste.
Grate 4 oz of Swiss cheese. Blend half of it into the white sauce. Add the pasta to the sauce, mix well, and pour back into the oven dish. Tamp well and smooth the surface with a spoon, sprinkle the rest of the cheese and a small handful of bread crumbs on top, and place in the oven.
Bake until the surface has browned nicely, about 20 minutes. Meantime, do the dishes. Don't let milk or cheese residues dry unattended.