Wash the meat, dab dry and rub with salt and pepper. Peel onions, halve two onions and finely dice the rest of the onion. Clean, wash and cut the leek into large pieces.
Place the meat, halved onions, leek and peppercorns on a fat pan and bake in a preheated oven (electric range: 175 °C / gas: level 2) for approx. 2 hours. After half of the frying time, deglaze the roast with 1/2 litre stock.
In the meantime, clean, wash and slice the carrots. Clean, wash and chop the turnip. Heat oil in a pot, fry the diced onions in it, add lentils, deglaze with remaining stock and simmer for 50-60 minutes at medium heat.
Cook turnips in boiling salted water for about 20 minutes, add carrots after about 5 minutes of cooking time and cook until done. After the end of the cooking time, drain the carrots and turnips on a sieve and mix into the lentils.
Take the roast out of the oven, cover and let it rest for about 10 minutes. Pour roast stock through a sieve into a pot and add cream. Bring to the boil, stir in sauce thickener, bring to the boil again and season with salt, pepper and paprika.
Serve the meat, sprinkled with coloured pepper to taste, with the vegetables and parsley leaves on a plate. Serve with sauce extra.