This tomato sauce is easy to prepare year round. It freezes very well, and the recipe can be doubled—so you can have some on hand any time a basic sauce is called for.
Drain the tomatoes, reserving 1cup of the juice. Crush the tomatoes with the back of a spoon, and set aside.
Heat the oil in a saucepan over medium-low heat. Add the onions, carrot, and garlic. Cook, stirring, until the onions and garlic have wilted, about 10 minutes.