Fresh Tomato Sauce

Makes about 3 cups

Ripe and dense plum tomatoes – pomodori maturi – in Italian are crucial for making this very simple sauce. This base can be used wherever tomato sauce is called for and will marry beautifully with other flavors added to it, whether herbs, diced prosciutto or salami, seafood, mushrooms, or cheese. Multiply the recipe to have it on hand. A good trick after peeling the tomatoes is to squeeze the skins a handful at a time to release the precious pulp and tomato water and add it to the puree.

Puree the tomatoes in a food processor or pass through a food mill. Heat the onion and olive oil together in a nonreactive saucepan large enough to hold the tomato puree over medium-low heat. A pot lined with stainless steel works best because it will not affect the flavor of the sauce. Cook, stirring from time to time, until the onion is very soft, translucent, but not caramelized, 5 to 8 minutes from when the onion starts to sizzle.

Add the tomato puree, salt, and sugar. Stir to combine with the onion and oil. Adjust the heat so that the sauce boils slowly and evenly, stirring from time to time from the bottom so the tomato solids do not cluster and burn. Simmer until most of the water has been cooked out and the sauce starts to thicken, 35 to 40 minutes. The bubbles in the sauce will appear to be resting in the top surface of the sauce. Check the seasoning and add salt or sugar to taste if needed. The sauce can be refrigerated for up to a week or frozen for up to 3 months.