Marcella's Miracle Tomato and Butter Sauce

I have already written about Giuliano Hazan's recipe in which he adapted his mother's original recipe, slicing the onion instead of cutting it in half, and it is very good. But it's high time I mentioned the original because it's a miracle recipe - so much more than the sum of its simple parts. And if you use excellent butter and from-Italy Italian tomatoes, it is so delicious you will find yourself just wanting to eat it straight out of the pan.

Marcella's Miracle Tomato and Butter Sauce

Adapted from Essentials of Classic Italian Cooking by Marcella Hazan

Serves 6

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

1 400g can of 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 cheese

Put the tomatoes in a saucepan, add the butter, onion halves, and a little salt, and cook uncovered at a slow simmer for 30 minutes or until the fat floats free from the tomato. 

Stir occasionally, taste, and add more salt, keeping in mind that you will add some parmigiano-reggiano cheese at the end. Discard the onion, and toss the sauce with pasta. Then add some parmigiano cheese and toss again.