Her most famous recipe. The New York Times agrees here (though they leave out the sugar.) From The Classic Italian Cookbook, Marcella Hazan, 1973.
TOMATO SAUCE III
This is the simplest and freshest of all tomato sauces. It has no vegetables, except an onion. The onion is not sauteed, it is not chopped, it is only cut in two and cooked together with the tomato. Except for salt and a tiny amount of sugar, the sauce has no seasonings. It has no olive oil, only butter. What does it have? Pure, sweet tomato taste, at its most appealing. It is an unsurpassed sauce for potato gnocchi, and it is excellent with spaghetti, penne, and ziti.
For 6 servings
2 pounds fresh, ripe, plum tomatoes
1/4 pound butter
1 medium yellow onion, peeled and halved
Salt
¼ teaspoon granulated sugar
1. Wash the tomatoes in cold water. Cut them in half, lengthwise. Cook in a covered stockpot or saucepan until they have simmered for 10 minutes.
2. Purée the tomatoes through a food mill back into the pot. Add the butter, onion, 1½ teaspoons salt, and sugar and cook at a slow but steady simmer, uncovered, for 45 minutes. Taste and correct for salt. Discard the onion.
If using canned tomatoes. Use 2 cups tomatoes and their juice, and start the recipe at Step 2.
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