Clean, wash and cut the soup greens into pieces. Onions peel, halve and cut into strips. Boil everything up with wine, vinegar and the spice ingredients. Let it cool down.
Wash the meat, dab dry and place in a large freezer bag with the marinade. Close the bag tightly. Marinate meat in the refrigerator for 2-3 days. Turn from time to time.
Lift meat out of the marinade, dab dry and season with salt and pepper. Heat clarified butter in a roaster. Brown the meat thoroughly all around. Add the marinade, vegetables and spices. Bring to the boil, cover and braise in a preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer) for approx. 1 1⁄4 hours.
Remove the roast from the stew and keep warm. Pour the stock through a sieve into a pot and bring to the boil. Crumble the gingerbread into it and simmer covered for about 10 minutes. Finely puree the sauce and season to taste with salt and pepper. Cut the roast into thin slices and serve with the sauce. Potato dumplings and red cabbage taste good with it.