Wash the meat, dab dry and season with salt. Heat the oil in a large pan or frying pan. Brown the meat all around, take it out. Place on a baking tray and cook in a preheated oven (electric cooker: 80 °C/ circulating air: not suitable/ gas: not suitable) for approx. 2 hours (check the core temperature with a roasting thermometer after 1 1/2 hours if necessary.
This should be about 60 °C). In the meantime, wash the rosemary, dab dry, pluck the needles from the stems and chop finely. Whisk 100 g butter with the whisk of the hand mixer until white and creamy.
Slice the nuts finely or cut them into thin slices. Fold egg yolks, breadcrumbs, nuts and rosemary into the butter. Season the butter with salt, pepper and a little sugar, form it into a roll (approx. 4 cm Ø) using cling film and let it set in the fridge.
Meanwhile bring 375 ml water and 1 teaspoon of salt to the boil and remove from the heat. Add 125 ml milk, stir in the puree powder with a whisk. Let it cool down. In the meantime, reheat frying set.
Deglaze with 350 ml water and sherry. Loosen the frying set, stir in beef paste and cream, bring to the boil and simmer for 2-3 minutes. Stir the starch with a little water until smooth, thicken the sauce slightly and set aside.
Cook vegetables in boiling salted water for about 7 minutes. Stir egg and flour into the mashed potatoes, season to taste with nutmeg, salt and pepper. Form small, pear-shaped dumplings (50 g each) from the potato mixture and fry them in a pot with plenty of hot oil until golden brown and keep them warm.
Take out the vegetables and rinse with cold water. Take out the meat. Cut 1 cm thick slices from the nut-butter roll. Cover the meat with the overlapping slices and press them on. Grill the meat under the grill of the oven for about 5 minutes until golden brown.
Melt 1 tablespoon of butter. Swivel the vegetables in it for about 4 minutes, season with salt and pepper. Remove meat, cut into slices and arrange on preheated plates with potato pears, vegetables and sauce.