Peel and finely chop the onion. Fry in 1 tbsp. hot oil. Sprinkle sugar over it and melt golden yellow. Add the sauerkraut and fry. Season with salt, pepper and 2 tsp. sweet paprika. Add cream and juice, bring everything to the boil. Stew for about 15 minutes.
Wash the fish, pat dry and cut into 4 pieces. Sprinkle with lemon juice and let it stand for a while
Pour the sauerkraut into a lightly oiled casserole dish. Season fish with salt and pepper and place on top. Stir crème fraîche and 1/2 teaspoon paprika until smooth, spread on the fish. Cook in the preheated oven (electric cooker 200 °C/circulating air: 175 °C/gas: level 3)for 15-20 minutes. Goes well with mashed potatoes
Drink: cool white wine