For the sauce, wash the bones, dry them, mix with a little oil and place on a baking sheet. Roast at 200 degrees top / bottom heat for 40 minutes.
Finely dice onions, celery and carrots and fry in a large saucepan until they take on a little color. Add the tomato paste and roast.
Add the bones and pour 5 liters of water and the wine on top. Add the bay leaves and peppercorns and bring to the boil, then reduce the heat and simmer for 10 hours with the lid open.
After the cooking time, remove the bones and drain the sauce through a sieve. Degrease the sauce with a kitchen roll / cloth. Season to taste with salt.
Remove individual leaves from the Brussels sprouts. Bring the water to the boil and add plenty of salt. Cook the Brussels sprouts leaves in the salted water for 2 minutes.
Put water, ice cubes and plenty of salt in a bowl and quench the cooked Brussels sprouts so that they keep their green color. Remove the Brussels sprouts leaves from the water and set aside. Briefly toss the Brussels sprouts through clarified butter before serving.
For the venison fillet, first season the meat with salt and pepper. Then cut into pieces approx. 12 cm in size and put 2-3 pieces each in a vacuum sealing bag.
Crush the juniper berries in a mortar, press or cut the garlic with a knife and distribute both on and under the meat. Also put the thyme in the bag and vacuum seal everything using a vacuum sealer.
Let the meat steep in the refrigerator for a few hours, preferably. Later cook the meat in the sous vide cooker at 55 degrees for 40 minutes.
In the meantime, peel the Jerusalem artichoke and potatoes for the Jerusalem artichoke puree, cut into pieces and cook in salted water for 25 minutes (make sure that the Jerusalem artichoke is cooked quickly after peeling, otherwise it will turn brown).
Before pureeing, pour off the cooking water completely, then add the butter. Season to taste with salt, nutmeg and pepper.
Clean the king oyster mushrooms, cut in half lengthways and score in a diamond shape. Season with salt and pepper and fry in the pan with the thyme and garlic.
Sear the meat in the pan, take it out of the pan and then let it rest for 10 minutes. For serving on the plate, cut the meat diagonally, cut off the ends so that the meat stands up to stand.