Cooking tomatoes briefly and then straining them creates a thick liquid known as tomato purée. By cooking tomatoes for a longer period and further reducing the liquids, a thicker, richer tomato paste is created. Neither tomato purée nor tomato paste has any seasonings added. Preparing your own tomato purée from tomato paste is a process that takes just a few steps and allows you to substitute tomato paste in recipes that call for tomato purée.
Place 2 tbsp of tomato paste in a measuring cup.
Add water to make one cup.
Place the water and tomato paste in a saucepan.
Whisk the tomato paste and water together in the saucepan, breaking up thick clumps of paste, until you have a smooth purée.
Use tomato paste in place of tomato purée in recipes that require additional liquids, like soups, by reducing the amount of liquid in the recipe by slightly less than 1 cup.