Peel, wash and roughly grate the potatoes. Stir in egg yolk. Season with salt and pepper. Heat 1 tablespoon of oil in a frying pan. Shape the potato mixture into 4 small Rösti and fry over a low heat for about 5 minutes.
Turn the Rösti halfway through the frying time. Keep the finished Rösti warm. Wash the meat, dab dry, cut in half lengthwise and season with salt and pepper. Spread the cheese on the roulades and smooth it down.
Sprinkle with pistachios, roll up and pin with wooden skewers. Heat 1 tablespoon of oil and fry the roulades for about 10 minutes, turning them over. Clean, wash and cut the cabbage into pieces. Peel onion and cut into fine cubes.
Heat the fat and fry the cabbage and onion while turning. Add cream and milk, bring to the boil and cook for about 8 minutes. Season with salt and pepper. Arrange on a plate.