In a Dutch oven, brown meat in oil on all sides over medium-high heat. Remove roast and set aside. Drain, reserving 1 tablespoon of drippings. Saute the onion, mushrooms and garlic in drippings until tender.
Return roast to the pan. Add the broth, bay leaf, salt and pepper; bring to a boil. Reduce heat; cover and simmer for 1-1/2 hours. Add barley. Cover and simmer for 45 minutes or until meat and barley are tender. Add peas; cover and simmer for 5 minutes or until peas are tender.
Discard bay leaf. Set the roast and barley aside; keep warm. Skim fat from pan juices. If desired, add sour cream to the pan juices; stir until heated through over low heat (do not boil). Slice roast; serve with barley and gravy.