Place meat in bowl and cover with onion, peppercorns, bay leaf and cloves. Add vinegar and wine and let marinate for four days in the refrigerator. Turn meat once each day to coat well. After four days, remove meat from marinade and dry well. Discard marinade.
Heat clarified butter in large casserole dish and brown meat quickly on all sides. Season with salt. Add water to side of pan and add some rye bread crust. Simmer gently, covered, for one hour, turning meat from time to time and adding more water when necessary.
When cooked, place meat on serving dish. Mix together cornstarch with water and add to gravy to thicken. Serve sauce on side.