For the crust, finely grind white bread in the universal chopper. Coarsely chop the nuts. Wash parsley and chop finely. Knead everything with 4 tbsp. butter and lemon juice. Season with a little salt.
Savoy cabbage clean, wash, quarter and cut into strips from the stalk. Peel and finely chop the onion. Fish wash, dab dry and in.
Cut 6 pieces. Peel and wash the potatoes, cover and cook in salted water for about 20 minutes.
Fry cabbage and onion in 1 tbsp. hot butter. Season with salt, pepper and nutmeg. Pour 100 ml water and cream, add stock and bring to the boil. Covered cabbage and cook for about 15 minutes.
Heat the oil in a frying pan. Fry the salmon for 1 minute on each side. Season with a little salt and pepper. Place on a baking tray lined with baking paper and spread nut mixture on the fish. Bake in a preheated oven (electric cooker: 225 °C/circulating air: 200 °C/gas: level 4) for 7-8 minutes.
Roast the mustard seeds in 1-2 tablespoons of hot butter. Heat milk. Drain potatoes, add milk. Mash to puree with a potato masher. Season to taste with mustard and salt. Arrange everything. Spread mustard butter over the puree.