Potatoes peel, wash and in thin slices plan or cut. Place the roof tiles in a greased gratin dish. Mix 150 g cream and milk. Season with salt and pepper and pour over the potatoes.
Bake gratin in the preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3) for about 45 minutes.
Peel the onions. Dice one and cut the other into fine slices. Clean, wash and halve the savoy cabbage and cut out the stalk. Cut cabbage small and bacon into fine strips.
Wash the pike-perch fillet and dab dry. Cut into 6-8 pieces. Cut the skin side 2-3 times. Sprinkle evenly with lemon juice.
Heat 1 tablespoon of clarified butter in a wide saucepan. Fry bacon in it until crispy. Add diced onion and fry briefly. Take out both.
Fry the onion slices in the hot fat of the bacon. Add the savoy cabbage and steam briefly. Season with salt and pepper. Pour a good 100 ml of water and 100 g of cream. Add stock and bring everything to the boil. Cover the savoy cabbage and stew for 15-20 minutes.
Season pike-perch fillet with salt and turn it in flour. Season the savoy cabbage with nutmeg.
Fry the fish in a large pan in 2 tablespoons of hot clarified butter only on the skin side at medium heat for 3-4 minutes. Turn and fry for another 2-3 minutes. Heat bacon and onions briefly. Arrange fish with diced bacon and onions on the savoy cabbage.
Add gratin.