Rinse the shiitake mushrooms and set them aside to soak in plenty of water. They will need about an hour to soak. Chop the onions, celery, and carrots. Put the vegetables and Michelle's seasoning in a large stock pot with the water. When the mushrooms are soft, snip them into smaller pieces (approx. a square inch each) and drop them in the pot. Bring the pot to a boil, turn down to simmer. Cook until the carrots just start to soften. Add barley and simmer for another 10-15 minutes. Taste the broth occasionally while cooking, add salt to taste and more of Michelle's seasoning if needed.