Clean and wash the vegetables. Cut carrots into fine slices, kohlrabi, leek and celery into thin strips. Bring 1 litre of salt water and wine to the boil. Wash and slice lemon.
Trout wash. Add the fish and lemon slices to the stock and let it simmer at low heat for 15 minutes. Heat the fat in a saucepan. Steam vegetables in it while turning. Season with salt and pepper and keep warm.
Heat 1/8 litre of water, add sauce powder and bring to the boil while stirring with whisks. Cut butter into pieces. Add to the sauce gradually over a low heat and continue beating until the fat has melted.
Stir in orange juice. Arrange the trout with the vegetables on a plate. Garnish with lemon balm. Add sauce sprinkled with orange peel. Boiled potatoes taste good with it.