Onions and tomatoes do good things for each other, the sweetness of one merging into the tartness of the other to produce flavor that is at once mellow and fresh.
Only the onion in this sauce is cooked at length, simmered in a covered pan until it is tender and lightly colored. The fresh tomatoes are diced small so they can be cooked quickly at high heat. The heat must be turned off before they dissolve, when they still retain some body in their consistency.
© 1986 Marcella Hazan estate. All rights reserved.