Melt butter in a large stock pot then sauté the onion and garlic until soft and translucent.
Add the mushrooms and lemon juice and toss well, simmer until mushrooms are soft.
Add the herbs, seasonings, and bay leaves, and stir well, continue to simmer a minute or so.
Add the beef stock, pearled barley, and carrots, and then bring to a boil. Reduce heat and then simmer on low heat for 1 hour, or until barley is cooked through and soft.