Cook the pasta in plenty of boiling salted water. Foam the butter in a saucepan, pour in the flour all at once and sweat briefly. Pour in the milk and cook for 3 minutes while stirring. Stir in the nutmeg and season sparingly. Finely dice the cheese and cut the ham into strips.
Stir the pasta and ham into the bechamel sauce and pour into a baking dish. Spread the cheese over it and bake for 20 minutes at 160 ° C.