Roughly dice the celery, carrots, onions, parsley root. Season the meat with salt and pepper and fry it together with the bones in oil until nicely browned all around. Then add the diced root vegetables and fry. Keep stirring so that nothing burns. After three minutes, add the sliced leek. Roast briefly. Add the coarsely ground (better: crushed in a mortar) peppercorns and the juniper berries cut in half with a kitchen knife. Extinguish with red wine and fill up with clear soup.
Stew the roast with the lid closed at a low temperature for 3 to 4 hours, or in the oven at 90°C. Remove the meat and keep it warm. Now remove the meat and keep warm. Strain the sauce through a fine sieve, remove the bones and vegetables. Either thicken the sauce with a little bit of cornstarch or (even better) reduce it to the desired consistency by boiling it for a longer time. A few minutes before serving, cut the meat into thin slices and warm them in the sauce.
Make the savoy leaves in salted water for about 20 seconds, then quench in iced water. Rub dry and remove the stem. Finely dice the onion. Blanch (scald) the tomatoes with boiling hot water, skin, seed and dice them as well. Clean the mushrooms and cut them into thin slices.
Sauté the onion cubes in a little oil until translucent. Now add the whipped cream