Wash the turkey. Pat the meat dry. Heat 6 tablespoons of oil in 3 portions in a frying pan, fry the meat one after the other, turning it well, and remove. Deglaze frying pan with 250 ml water, bring to the boil, drain and set aside.
Season meat with salt and pepper. Place on a fat pan and bake in a preheated oven (electric range: 100 °C/ convection oven: not suitable/ gas: not suitable) for approx. 1 3/4 hours. In the meantime, roast almonds in a pan without fat while turning.
Grind the porcini finely in the universal chopper and pour 1 litre of boiling water over them. Peel potatoes, wash and cook in boiling salted water for about 20 minutes. Grate parmesan finely. Drain potatoes and let them steam.
Press through a potato ricer. Stir in 4 egg yolks, 6 tablespoons of milk and butter. Season to taste with salt, pepper and nutmeg. Pour into a piping bag with a large star-shaped spout and squirt 15 spiral-shaped duchess potatoes each onto 2 baking trays lined with baking paper.
Whisk 2 egg yolks and 4 tablespoons of milk, carefully brush the potatoes with it and sprinkle with parmesan. Cover and put aside. Clean the cabbage, cut into quarters and cut out the stalk. Cut cabbage into strips and wash.
Peel the shallots. Clean and clean the mushrooms and possibly halve them. Wash thyme, shake dry, put some stems aside for garnishing, and pluck leaves from the stems. Heat clarified butter in a casserole, sauté cabbage in it, season with salt, nutmeg, pepper and cinnamon, deglaze with juice, bring to the boil and stew covered for about 8 minutes.
Add almonds. Bring the roasting pan to the boil again. Heat 2 tablespoons of oil in a large frying pan, fry the mushrooms in it while turning them, remove. Add the shallots to the frying fat and also fry well.
Add the mushrooms and thyme, except for something to garnish, and fry briefly. Season with salt and pepper. Deglaze with porcini water, frying set and cream, bring to the boil and simmer at low heat for about 5 minutes.
Stir in the sauce thickener, bring to the boil again, season with salt, pepper and sugar. Keep warm. Remove the meat from the oven, cover and let it rest for about 5 minutes. In the meantime, bake the duchess potatoes in a preheated oven (fan oven: 175 °C) for about 12 minutes.
Cut the meat open, place it on an ovenproof dish and spread porcini mushroom shallots cream over it. Keep warm in the oven with the duchess potatoes. Serve one slice of meat with porcini shallots cream, duchess potatoes and vegetables on plates garnished with thyme.