Cover dried mushrooms with 1 cup boiling water, and set aside for 20 minutes.
Prepare fresh, cleaned mushrooms, garlic, onion, carrots and celery and set near the stove for the soup assembly.
Heat a heavy-bottomed soup pot over medium heat.
Add olive oil, onions, carrots and celery and sauté until onions begin to color, about 10 to 15 minutes. Stir often.
Add garlic, and sauté for 30 seconds.
Add fresh mushrooms, and cook until they begin to release liquid, about 5 to 10 minutes. Raise heat and add oat berries and sauté until it begins to color.
Add broth, wine and tomato paste.
Drain dried mushrooms and finely chop; strain mushroom-soaking liquid to remove any grit and add to pot along with the reconstituted mushrooms.
Season with sea salt and freshly ground black pepper, and simmer for about 40 minutes, until barley is just tender. Adjust seasonings and serve with minced fresh parsley or chives and/or a dollop of crème fraîche, (optional of course).