Wash, peel and cut the potatoes into pieces. Cook in boiling salted water for about 20 minutes. Wash parsley and shake dry. Pluck off leaves and chop finely, put something aside for garnishing.
Mix parsley with cream cheese and 100 g crab meat. Season with pepper.
Wash fish, pat dry, cut fillets in half. Spread the cream cheese on the fish, fold it up and press it down a little. Season with salt and pepper and turn in flour. Heat oil in a coated pan.
Fry the fish for 5-6 minutes on each side, remove and keep warm.
Peel and finely chop the garlic. Melt 50 g butter in a pot, add garlic and milk. Leave to stand briefly. Drain the potatoes and let them evaporate briefly. Add milk mixture and mash to puree.
Season to taste with salt and nutmeg. Heat 4 tablespoons of butter in a frying pan, brown lightly. Remove from heat and add 150 g crab meat. Serve the fish with mashed potatoes and crab butter. Sprinkle with parsley.