For the smoked trout puree, soak the gelatin in cold water. Cut the smoked trout with the skin into cubes – set aside 2 tablespoons without skin.
Heat the butter in a saucepan and sauté the onions. Add the trout cubes and sauté briefly. Deglaze with vermouth and white wine and pour in the vegetable soup. Season with lemon juice and zest, dill, salt and pepper and stir in 150 ml liquid cream. Simmer for a few minutes.
Strain through a hair sieve and stir in the soaked, squeezed gelatine. Whip the remaining cream and fold into the slightly cooled mixture. Finally, mix in the trout cubes that have been set aside.
Pour the trout puree into cold rinsed ramekins and let it set in the refrigerator for at least 3 hours.
Peel the kohlrabi and cut into fine sticks. Turn the smoked trout puree out onto small plates and garnish with the kohlrabi strips.