I like to use a combination of mild and sharp cheese. Using just sharp cheese will decrease the lovely flavor of the smoked ham. Oh--and the smokier, the better. Some good combinations include Monterey jack with sharp cheddar, Swiss with mozzarella, or a mild white cheddar with Stilton (don't use more than 1/4 Stilton or you'll be overpowered). But since this is a quickie dish, you can simply use what you have on had, even if that's just a single cheese.

1 8-ounce package elbow macaroni
1/4 pound thinly sliced smoked ham, broken into tiny pieces
1 bunch leeks OR scallions, chopped
salt and pepper
2 tablespoons flour
2 tablespoons butter
2 cups milk
a generous splash of white wine OR vermouth (optional)
crusty bread OR store-bought Italian-style breadcrumbs
2 cups grated cheese (see cheese suggestions, above)

Preheat oven to 350°. Cook the pasta in a pot of salted water, according to package directions.

Meanwhile, make a roux: In a saucepan over medium heat, melt the butter and then sprinkle in the flour, stirring constantly. By the time the mixture has an even consistency, it will be as cooked as it needs to be.

Reduce heat. Stir in the milk, whisking constantly to avoid lumps. Simmer the mixture for about 4 minutes, stirring constantly to prevent scalding.

Add the cheese, simmer another 3 or 4 minutes, stirring frequently to prevent burning. If you wish, stir in a splash of white wine or vermouth. Salt and pepper to taste. Remove from flame and set aside.

Place the cooked and drained pasta in an oven-safe dish. Add the ham and onions, and mix using a wooden spoon.

Pour the cheese sauce over the macaroni mixture, top with a very thin layer of breadcrumbs or torn French bread crust pieces, and bake in a 350° oven for about 15 minutes.

Let finished dish set up for about 5 minutes before serving. The sauce will be thinner than a typical American mac and cheese.