I had some fire roasted canned tomatoes, but it lacked sweet and thick, so out comes the ketchup to replace the paste. You don’t need much, so don’t overdo it. I also could have used barbecue sauce in place of the ketchup to achieve the same goals. Interesting. Next time I’ll be sure to have on hand what’s needed for a barbecue marinara.
Don’t let the arrogance of others get in your way of creating new product. Ketchup can be used in many sauces, soups and gravies to add richness that might be missing otherwise. The same with mustard and barbecue sauces. They have a distinct culinary purpose. Don’t hold back exploiting it.