I used to think a good Italian tomato sauce involved hours at the stove and a long list of ingredients. Then I made this for the first time, a recipe invented by a famous Italian cookbook author named Marcella Hazan. It was an eye-opener because the sauce was so surprisingly simple, yet flavorful. You don’t even have to bother chopping the onion; just cut it in half and throw it in. Who needs pasta sauce from a jar with a recipe like this?
Empty the can of tomatoes with the juices into a medium pot. Add a few tablespoons water to the can, swirl, and empty any remaining juices to the pot. Use your hands to squeeze the tomatoes so they break up into smaller pieces.
When the sauce is almost done, cook the pasta in a large pot of salted water. Drain well.
Scoop out the onion halves and discard or reserve for another use (see Notes). Taste the sauce and add more salt, if needed.
Toss the pasta with the sauce and serve, with freshly grated Parmesan to add at the table.
You can try repurposing the cooked onion by blending into a pureed soup, adding it to a veggie or chicken broth, blending it with beans, or adding it to a batch of mole.