
Place roast in a 5-qt. slow cooker; add broth, onions and seasonings. Cook, covered, on high for 4 hours. Add potatoes, carrots and mushrooms. Cook, covered, on high 1 hour longer or until vegetables are tender. Remove meat and vegetables; keep warm. Discard bay leaf.
In a saucepan, combine flour and cold water until smooth; stir in 1-1/2 cups cooking juices. Bring to a boil. Cook and stir until thickened, 2 minutes; add browning sauce. Serve gravy with roast and vegetables and, if desired, top with additional green onions.