Mushroom Barley Soup with Shaved Parmesan

extra-virgin olive oil

medium yellow onions, chopped

celery stalks, chopped

carrots, chopped

garlic, minced

chopped mushrooms, a mix of button, shitake and portobellas

reduced-sodium beef broth, more to add the next day if too much liquid gets soaked up

dry sherry

barley

kosher salt & freshly ground black pepper

shredded parmesan, for topping