Put the meat into a high-sided casserole containing oil, butter and marrow, together with the chopped mixture of carrot, celery, onion and parsley. Brown over high heat and, during this first phase, turn the meat gently so it becomes nicely golden all over. Add the wine (white for the veal amd red for the beef), the tomato conserve, and the mushrooms previously soaked in warm water. Lower the heat and cook for 15-20 minutes. Cover the meat with a good stock. Turn the heat down to the minimum and reduce the sauce, after adding a tablespoon of flour, for about 1 hour. Sieve the sauce and it is ready. Recommended for dressing ravioli.