It's a sound principle, so why not apply it to vegetable soups? Many recipes for vegetable soup don’t start with that robust base of vegetable broth, so you miss out on the deep flavor that broth brings to the table. But you don’t have to.
Using the whole vegetable—nose to tail, so to speak—ensures that no opportunity for vegetable flavor is wasted.
For example, we love to simmer tough shiitake mushroom stems along with the caps to make mushroom broth for soba noodles. And you can puree some soft cooked scraps, like sweet potato skins, broccoli stems, or cauliflower cores, right into a vegetable soup.