For the pumpkin seed crust, cream the butter with the egg yolk. Season with garlic, pepper and salt. Finely chop the pumpkin seeds and add with the white bread crumbs. Mix thoroughly.
For the pike perch, season the fish with salt as well as pepper and sprinkle with lemon juice. Heat oil or butter in a frying pan and sear the walleye fillets on both sides for a total of 4-5 minutes. Dab with kitchen roll and place fillets on an ovenproof plate.
Then apply the pumpkin seed mixture and gratinate in the preheated oven at maximum top heat (or under the broiler) until light brown.
Remove the finished pike perch from the tube and serve hot.