Brush mushrooms to remove any soil that may be clinging to them. Rinse under cool
water and drain. Trim stems and cut into bite-sized pieces, remembering that mushrooms
shrink when cooked.
Heat olive oil in a large soup pot
over medium-high heat. Add onion and mushrooms. Stir until onions are tender and
translucent and mushrooms give up their moisture. Add barley, broth, water, and
tomatoes. Bring to a boil, then reduce heat to medium-low and simmer for 15 minutes
until barley is tender.
Turn off heat. Use a vegetable peeler to put thin strips of carrot into soup. Add