Marcella's Miracle Tomato and Butter Sauce

Adapted from Essentials of Classic Italian Cooking by Marcella Hazan (Knopf, 1992)

Serves 6

I’ve already written about Giuliano Hazan’s version of this sauce, in which he thinly slices the onion instead of halving it, and it’s very good. But it’s high time I mentioned the original, because this one is a miracle—so much more than the sum of its simple parts. If you use excellent butter and from-Italy Italian tomatoes, it’s so delicious you may find yourself wanting to eat it straight from the pan.

Because you want to sauce the pasta lightly, this is enough for 1 pound of pasta. If you're making less than that, you can freeze the leftover sauce—just do so without the onion and without any cheese.

One 400g can Italian plum tomatoes, cut up with their juice
5 tablespoons butter (don’t skimp here)
1 medium onion, peeled and cut in half
Salt
Freshly grated Parmigiano-Reggiano

Put the tomatoes in a saucepan. Add the butter, onion halves, and a little salt. Simmer uncovered over low heat for about 30 minutes, or until the butter separates from the tomato.

Stir occasionally, taste, and adjust the salt—keeping in mind you’ll add cheese at the end. Discard the onion. Toss the sauce with pasta, then add Parmigiano and toss again.