Tomato paste is the most concentrated of all the cooked-tomato products — a thick, deep brick-red purée made by simmering ripe tomatoes for hours until almost all their water is driven off and only the dense, intensely savoury fruit solids remain. A spoonful carries a powerful charge of sweet-sour tomato flavour and glutamate-rich umami, which is why cooks use it not as a sauce in itself but as a flavour base — stirred into soffritto, braises, stews, ragùs and tomato sauces to deepen and round out the whole dish.