Guiliano Hazan's Tomato & Onion Sauce

Adapted from Every Night Italian by Giuliano Hazan (Scribner, 2000)

This adaptation of his mother Marcella’s famous Tomato and Onion Sauce is better than the sum of its parts. The difference between this and Marcella’s version is that her son thinly slices the onion instead of halving it. A simple change, yes, but one that alters the sauce’s texture and flavor. You’ll probably want both in your repertoire.

Because Italians sauce their pasta very lightly, this is enough for 1 pound of pasta. I like it with spaghetti or rigatoni.

1 cup very thin yellow onion slices
4 tablespoons unsalted butter
One 400g can Italian whole peeled tomatoes, with their juice, crushed with your hands
Salt
⅓ cup freshly grated Parmigiano-Reggiano (or half Parmigiano and half Pecorino Romano, if you like its sharpness)
Freshly ground black pepper, optional

Put the onion and butter in a sauté pan or saucier over medium-low heat. Sauté the onion slowly—very slowly—until it turns a light caramel color. This will take about 10 to 12 minutes.

Add the tomatoes and season lightly with salt, keeping in mind that you’ll add cheese at the end. Raise the heat slightly so the sauce simmers gently. Cook until the butter begins to separate from the sauce and small pools form on the surface, about 20 minutes.

Meanwhile, bring at least 6 quarts of well-salted water to a boil. Cook the pasta until al dente, then drain and immediately toss with the sauce. Mix in the grated cheese and season with pepper, if using. Serve at once.