Marinate beef in one third of brandy and red wine for at least 1 hour. Turn occasionally. In large heavy skillet heat half the butter until foamy.Mix together flour with salt and pepper to taste. Roll beef cubes in flour, place in hot butter and brown, removing cubes as they are done. In separate skillet, heat remaining butter; add onions; stir, cover and simmer over low heat 2 min. Add mushrooms, turn up heat and saute' 3 minutes. Remove from heat; add tomato paste,garlic and 1 tbl flour. Mix until smooth. Add remaining brandy, red wine, beef stock, bay leaf, thyme, salt + pepper to taste. Boil, reduce heat. Simmer 15 min.Add beef and simmer 1.5 hours.