Combine the broth, barley, zucchini, carrots, celery, minced onion, chives, and pepper in a large soup pot; bring to a boil. Reduce heat to medium and cook 25-30 minutes, or until the vegetables soften. Add 1-2 cups of water along with the mushrooms, green onions, miso, and sherry. Cook another 5-7 minutes. Add more water if you feel it’s too thick. Stir in the parsley. Serve and enjoy!