Wash the redfish fillets, dab dry and cut diagonally into 6 cm wide slices. Sprinkle with lemon juice, salt and let stand for 20-30 minutes. In the meantime clean and wash the pointed cabbage and cut it roughly into strips.
Wash and halve the tomatoes and remove the seeds with a teaspoon. Cut the tomato halves into slices. Heat 30 g fat in a pot and braise the cabbage in it. Season with salt and pepper, pour on 125 ml broth and stew covered for about 10 minutes.
Add the tomato slices approx. 2 minutes before the end of the cooking time and cook along. Peel and finely dice the onion. Steam until translucent in the remaining hot fat. Add remaining stock and cream, bring to the boil and sprinkle in the sauce thickener while stirring.
Bring to the boil again briefly and season to taste with salt, mustard and a little sugar. Add mustard sauce to the vegetables and keep warm. Mix the egg with a little salt and pepper in a deep dish. Flour and breadcrumbs separately in deep plates as well.
Dab fish slices dry and turn them first in flour, then in egg and finally in breadcrumbs. Heat the oil in a pan and fry the fish for 5-6 minutes, turning. Arrange on a plate with the pointed cabbage.
Serve garnished with dill blossom as desired.