Peel and finely chop the onion. Clean the savoy cabbage, cut into fine strips and wash. Heat the fat in a pot and fry the onion. Add the savoy cabbage and steam briefly. Dust with flour and sauté for about 2 minutes.
Deglaze with broth and bring to the boil. Stir in cream cheese and cook covered at medium heat for about 10 minutes. In the meantime cut salmon into strips. Take out some savoy cabbage with a skimmer and let it drain.
Finely puree the rest of the soup, bring to the boil, season with salt and pepper. Add the rest of the savoy cabbage and arrange in cups. Serve garnished with salmon strips, black pepper and horseradish shavings.
Toasted toast bread tastes good with it.