Peel, wash and halve the potatoes and cook in boiling salted water for about 20 minutes. Drain the potatoes and swivel them dry on the still hot stove. Press them through a potato ricer.
Stir in 3 egg yolks and 5 tablespoons of milk, season to taste with salt and nutmeg. Pour into a piping bag with a large star-shaped spout and squirt about 16 duchess potatoes onto a baking tray lined with baking paper.
Whisk 1 egg yolk with 2 tablespoons of milk. Carefully brush the potatoes with it. Put in a cool place. Defrost puff pastry at room temperature. Clean savoy cabbage, remove outer leaves. Remove 4 large leaves from the head, cut thick veins flat and blanch in boiling salted water for about 2 minutes.
Take out and let drain. Wash the meat, dab dry and season with salt and pepper. Heat oil in a pan. Brown the meat thoroughly all around for about 5 minutes, remove. Wrap with bacon and savoy cabbage leaves.
Place puff pastry slices on top of each other and roll out thinly to a rectangle (approx. 25 x 35 cm) on a floured work surface. Wrap the meat in the puff pastry, brush thinly with the remaining egg yolk. Sprinkle with sesame seeds.
Cook in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 20 minutes. Cut the remaining savoy cabbage into coarse cubes from the stalk. Peel onion and cut into strips. Heat the fat in a saucepan.
Sauté onion until translucent. Add the savoy cabbage and season with salt and pepper. Pour on the stock. Steam in closed pot for about 8 minutes. Take the meat out, wrap in aluminium foil and let it rest. Bake potatoes in the oven at the same temperature for 10-15 minutes.
Pour red wine and 100 ml water into the pan, dissolve the frying set, bring to the boil. Stir starch and 3 tablespoons of water until smooth. Stir into the sauce, bring to the boil again. Season to taste with salt, pepper and sugar.
Cut the meat into slices. Arrange potatoes, vegetables and meat with sauce on plates. Sprinkle with pink berries.