My family is Turkish and we put tomato paste in everything. With onions, tomato paste and ground beef, one can cook any vegetable and it will be a Turkish dish. These are the basic ingredients for everything in Turkish cuisine.
When my mom needs a substitute fr tomato paste, she uses red pepper paste. We almost always have both at home, so if we run out of one, we can always substitute with the other. They don't taste exactly the same, but the flavors are very similar. Sometimes, my mom will put a little bit of both to make food taste better.