If I use unsalted paste, which is usually available at grocery stores in mine area, the only salt is what I add myself. The optional mushroom adds a more “earthy” taste. The optional squash adds a mellower, sweeter taste; similar to an earlier suggestion of carrots.
I should note that many people don’t like the taste of toasted garlic. If you don’t like it, don’t toast it, maybe by putting the onions in first and garlic second.