Combine first 10 ingredients - stew beef, onion soup, red wine, salt and pepper, potatoes, carrots, mushrooms, bay leaf, and rosemary. Cover and cook on low for 8 to 10 hours; add tomatoes about 45 minutes to an hour before done. Thicken with flour and water mixture about 20 minutes before serving, taste and add more salt and pepper if needed. Beef stew serves 6.