Defrost deep-sea crab meat at room temperature. Clean, wash and drain salads. Wash cherry tomatoes, grate dry and quarter them. Peel and halve the onion and cut into fine strips. Pluck the pickled salad into bite-sized pieces. Mix the salad, onion and cherry tomatoes and chill.
Peel and wash the potatoes, cut them into pieces and cook them in boiling salted water for about 20 minutes. Chop capers very finely. Cut deep-sea crabs into small pieces. Mix capers, cream cheese, mustard, crabs, egg yolk and breadcrumbs. Wash the dill and dab dry. Finely chop flags of 2 stems and add to the mustard cream. Wash fish fillets, pat dry and season on both sides with salt and pepper. Place them on a board with the skin side facing upwards. Spread about 1 teaspoon of mustard cream on each fillet. Roll up the fillets from the wider side and carefully pin the tail end with a toothpick. Heat oil in a coated pan and fry the rolls in 2 portions carefully all around for about 6 minutes at medium heat. Heat milk and fat.
Place them on a board with the skin side facing upwards. Spread about 1 teaspoon of mustard cream on each fillet. Roll up the fillets from the wider side and carefully pin the tail end with a toothpick. Heat oil in a coated pan and fry the rolls in 2 portions carefully all around for about 6 minutes at medium heat. Heat milk and fat. Drain the potatoes. Keep fried rolls warm and fry remaining rolls. Mash potatoes with a potato masher and gradually stir in the milk and fat mixture. Season to taste with salt and nutmeg. Add vinegar and olive oil to the salad and mix well. Season salad with salt, pepper and a little sugar. Arrange mashed potatoes with fish and salad and garnish with dill
Keep fried rolls warm and fry remaining rolls. Mash potatoes with a potato masher and gradually stir in the milk and fat mixture. Season to taste with salt and nutmeg. Add vinegar and olive oil to the salad and mix well. Season salad with salt, pepper and a little sugar. Arrange mashed potatoes with fish and salad and garnish with dill