Tomato paste is one thing I am always hunting for, and I often end up running to the store in the middle of recipe preparation. If you need a can of tomato paste or just a few tablespoons, but don't have a can or tube in your pantry, you can substitute with thickened, concentrated tomato sauce or canned tomatoes.
Also, blended canned tomatoes make a good substitute for tomato sauce for pizza or as a base for homemade pasta sauces.
How to Make Tomato Paste From Tomato Sauce
Pour a can (8 or 15 ounces) of tomato sauce into a saucepan and bring it to a brisk simmer over medium heat. Simmer, stirring constantly, for about 7 minutes, or until reduced by about two-thirds. Use a splatter screen to avoid a mess from the bubbling as the mixture thickens.
You should have about 3 to 4 ounces of tomato paste from an 8 ounce can, or about 6 or 7 ounces from a 15-ounce can.
How to Make Tomato Paste From Canned Tomatoes:
Blend a 14.5-ounce can of tomatoes in a blender or food processor until smooth,
Pour the tomato mixture into a saucepan. Bring to a boil over medium heat. Continue cooking, stirring constantly, for about 8 to 10 minutes, until thickened and reduced by about two-thirds.
You should get about 2/3 cup or 6 ounces or tomato paste from a 14.5 ounce can of tomatoes.
Note: To make tomato sauce from canned tomatoes, blend until smooth and use or cook over medium heat, stirring constantly, for about 3 to 4 minutes to thicken slightly.