In large skillet, in hot oil, cook (cut up) beef stew until browned. Set aside
In 4 qt slow cooker, place mushrooms, onion, garlic, oregano, thyme, salt, pepper, and bay leaf. Add browned beef. Pour beef broth & cooking wine over all ingred.
Cover and cook on high heat for 4-5 hrs. Or you can use low heat and cook for 8-10 hrs.Remove & discard bay leaf.
In med bowl, combine sour cream, water & cornstarch. Stir about 1 cup of the hot liquid into sour cream mixture. Stir sour cream mixture into cooker. Cover & cook for an additional 30 min or until thickened. If desired, just before serving sprinkle with parsley. Serve over cooked whole wheat pasta or brown rice.