Peel, wash and roughly dice the potatoes and boil them in salted water for about 20 minutes. Clean, wash and cook the beans in boiling salted water for about 8 minutes. Drain beans, quench and drain. Wash and clean the chanterelles if necessary. Peel and finely dice the shallot. Coarsely chop the nuts and roast them in a large pan until golden brown. Take them out.
For the steaks dab meat dry. Heat 1 tablespoon of oil in a frying pan. Sauté the steaks on each side for about 2 minutes. Season with salt and pepper. Wrap in foil and cook in a preheated oven (electric cooker: 100 °C/circulating air: 80 °C/gas: see manufacturer). Deglaze frying set with sherry, put aside.
For the puree, drain the potatoes. Add milk and 2 tablespoons of olive oil. Mash the potatoes coarsely. Season to taste with salt, pepper and nutmeg. Keep warm.
Heat 1 tablespoon of oil and butter in a second pan. Fry the chanterelles in it for about 3 minutes. Heat 1 tablespoon of oil in a saucepan. Sauté shallot in it until transparent. Add the beans and 2 tbsp. water and heat for approx. 2 minutes. Fold in nuts. Wrap the steaks out of the foil and pour the resulting gravy into the pan as a roasting mixture. Arrange everything.