If you are looking for viable tomato paste substitutes for your recipe, you may not need to look any further than your own pantry!
Tomato Paste Substitutes
There are many people who look for tomato paste substitutes when they want to change the flavor of their dish, avoid tomatoes for an allergy reason, or are simply lacking this particular ingredient at a crucial time! The production of tomato paste is quite labor-intensive and is therefore usually store-bought. Made only from highly reduced tomatoes and salt, it is used to add color and a succulent flavor to dishes and sometimes works as a thickening agent in sauces or soups. So, what should you do if you find yourself out of this ingredient? Well, rather than leaving it out entirely, we recommend trying one of these excellent substitutes that include tomato sauce or puree, canned or fresh tomatoes, red peppers, and butternut squash. 
Tomato Sauce or Puree
There are a number of differences between tomato paste and tomato sauce/puree. One is the consistency – tomato paste is thicker than both of these potential substitutes. The second is the flavor – many tomato sauces come flavored with other herbs, whereas paste is only composed of tomatoes and salt.
However, as the base ingredient is much the same, tomato sauce or tomato paste can be an easy-to-find alternative to tomato paste, particularly in pasta dishes. We recommend doubling the quantity to achieve a similar flavor. If it is a key ingredient, reduce the liquid elsewhere in the recipe so the consistency is maintained.
Canned or Fresh Tomatoes
You can reduce canned or fresh tomatoes down to make a thicker, paste-like consistency that offers similar flavors, although fresher and not as rich as the paste. Alternatively, you can try substituting for the canned tomatoes and reducing the whole recipe for slightly longer than normal to remove any excess liquid.
This is a good substitute if your main concern is the color and thickness of a dish. Blend the roasted peppers to make a paste and then add this mixture to your recipe in place of tomato paste. This is also a good alternative for those who don’t like tomatoes or have an allergy. Add a dash of lemon or a little citric acid to compensate for the acidic flavor that will be missing from the red peppers. 
Many people are surprised by this, but another vegetable can act as a substitute! Roast your butternut squash before blending it to make a paste. This can be a good alternative to tomato paste in curries. It offers the right kind of consistency, but not the red color. The flavor is different too, so be sure that you like the earthy, buttery squash taste before adding this substitute. Like red peppers, you might want to add a dash of something citrus to provide a little more tanginess to your dish.