Peel, wash and chop the potatoes. Cook in boiling salted water for about 20 minutes. Clean and wash the Brussels sprouts
Wash the meat, dab dry and cut a pocket lengthwise into each
Chop the walnuts, of which 2 tsp. finely chop the nuts. Mix cheese, aiwar and finely chopped nuts. Fill meat pockets with it and wrap with bacon. Heat oil in a large pan. Fry the chicken fillets with the bacon seam side down, turn them, also fry them and season with pepper and a little salt. Fry gently at medium heat, turning occasionally, for another 15 minutes.
Cook the Brussels sprouts in boiling salted water for about 15 minutes. Drain the potatoes. Heat the milk, pour it into the potatoes and mash them to a puree. Stir in truffle butter. Season puree with salt
Roast the remaining walnuts in a pan without fat, remove. Melt the fat. Drain the Brussels sprouts and arrange in a bowl. Pour fat over them and sprinkle with walnuts. Arrange mashed potatoes, chicken fillets and sprouts on plates, sprinkle with pepper