In a Dutch oven or stockpot, cook meat in oil over medium heat until no longer pink. Remove meat with a slotted spoon; keep warm and set aside.
Saute onions, carrots and celery in drippings over medium heat until tender, about 5 minutes. Add mushrooms, garlic and thyme; cook and stir 3 minutes. Stir in broths, water, barley, salt if desired and pepper.
Return meat to pan; bring to a boil. Reduce heat; cover and simmer 1-1/2 to 2 hours or until barley and meat are tender. Add parsley.