Boil the macaroni in plenty of water with a bay leaf. Add salt, and when the water boils, add the macaroni and a little oil. Cook until al dente.

Before draining the macaroni, reserve a cup of the cooking water. Rinse the macaroni with cold water and set aside.

In a pan, heat a little oil and add the onion, finely sliced into julienne strips. Sauté over low heat until well softened, then set aside, draining any excess oil.

To make the bechamel sauce, melt the butter in a saucepan. Once melted, remove from heat and add the flour, stirring to combine.

Slowly add the milk, stirring to prevent lumps, and also add a bit of the reserved pasta cooking water.

Add salt, black pepper, and nutmeg, continuing to stir the sauce to prevent it from sticking to the pan.

When the sauce begins to thicken, add the ham, cut into small cubes or long strips. Cook everything together for a couple of minutes.

Then add the macaroni and stir to mix everything well. If the sauce is too thick, add a little more cooking water or milk.

Place the macaroni in an oven-safe dish and sprinkle grated cheese on top. Broil in the oven until the cheese is slightly toasted, and your macaroni dish is ready to serve.