Wash the meat and dab dry. Season with salt and pepper and cover with bacon. Bake in the preheated oven (150-175 ° C/ gas: level 1-2) for about 3 hours. Pour 1/8 litre water every 30 minutes.
For the vegetables, clean and wash the leek and cut it into rings. Cook in 3/8 litres of boiling salted water for about 10 minutes. Also clean and wash porcini and chanterelles. Cut the porcini into slices.
Peel and finely chop the onion. Heat the fat. Fry onion and mushrooms for about 5 minutes. Season with salt and pepper. Add leek with cooking liquid and cream and bring to the boil. Add sauce thickener and season again.
Cut the roast without bacon and serve with the vegetables. Serve garnished with parsley.