Peel the potatoes and cook in boiling salted water for about 20 minutes. In the meantime clean, wash and slice the zucchini. Steam in the slightly boiling broth for about 8 minutes. In the meantime wash the crab meat.
Cut the trout fillet into small pieces. Wash the dill and chop finely, except for a few flags for garnishing. Stir cream, mustard and chopped dill into the stock. Carefully fold in the prepared ingredients and warm them up.
Season to taste with salt and pepper. Arrange the salmon on plates and serve garnished with dill flags.