Clean the red cabbage, cut into eighths and cut out the stalk. Cut the cabbage into strips. Peel and roughly dice the onion. Wash the meat, dab dry and season with salt and pepper. Tie meat with kitchen string to a roll.
Heat the oil in a frying pan. Brown the meat all around and take it out. Fry the red cabbage and onion in the frying fat for about 4 minutes. Deglaze with stock, vinegar and pear juice and bring to the boil. Add bay leaves and peppercorns.
Put the meat on top of the red cabbage. Close the roaster with aluminium foil. Let it braise in the preheated oven (electric cooker: 200 °C/ circulating air: 175 °C/ gas: level 3) for about 1 1/2 hours. Remove the foil about 30 minutes before the end of the cooking time.
Peel and quarter the pears, cut out the core. Cut pears into slices. Wash the grapes and pluck them from the stalks. Add fruit to the red cabbage about 20 minutes before the end of the cooking time. Take out meat, remove kitchen string.
Season red cabbage to taste again. Cut the meat into slices and arrange on the red cabbage.