Dust the meat with the flour, heat the butter, fry the meat well with the onions on all sides. Make sure that the onions don`t get too dark. Pour in the vinegar and let it evaporate completely. Sprinkle the meat with salt and pepper. Pour in the meat stock first, then the cream. Put on a tightly fitting lid, reduce the heat and simmer for about 3 hours. When the cooking time is over, cut the meat into pieces and serve with the nicely thickened sauce.