We love vegetables in our spaghetti instead of meat. I include tomatoes (canned these days as the deer eat anything that I plant but for herbs), a can of no salt kidney or other beans labeled no salt, sliced mushrooms, thin sliced zucchini, garlic, herbs such as fresh lemon thyme and basil, cinnamon, tumeric, and today I added a few tablespoons of a butternut squash that was not as naturally sweet as usual. I included half of a jar of a prepared sauce from the grocery store and the small bit of baked butternut squash gave the sauce some body and a very smooth texture.
I will always add some baked winter squash to future sauces as it thickened the sauce and added a hint of sweetness. Sometimes, I add a bit of honey to the spaghetti sauce.
