Coat beef with flour, shaking off excess. In a large non stick pot, heat oil over med high heat. Add beef; saute until browned, about 6 minutes. Place on a plate.
Add onions and mushrooms to pot; saute for 6 minutes. Add garlic; saute, stirring for 1 minute. Pour off fat. return beef to pot; stir in tomato paste, then broth. Add enough water to just cover; bring to a boil. Reduce heat to low, simmer until beef ids tender, about 1 1/4 hrs. skim off any foam.
Add carrots, potatoes and green beans. Cover partially , simmer for 15 min.
In a small bowl, mix cornstarch and cold water , stir into stew. Increase heat to boil uncovered for 1 min.. Sprinkle with parsley and serve.