Cut off the kohlrabi leaves. Wash young leaves, chop and put aside. Peel, wash and drain kohlrabi and potatoes. Cut both into small cubes. Peel and finely dice the shallots. Heat butter and sauté vegetables and shallots. Deglaze with broth and 1 tbsp. lemon juice, cover and cook for approx. 5 minutes
Wash the rocket, shake dry and cut off the coarse stems. Cut the rocket leaves into strips
Drain and collect the vegetable stock. Whip 3 tbsp lemon juice, 3 tbsp stock, salt, pepper and 3 tbsp oil and fold into the vegetable mixture. Add rocket and kohlrabigrün and season with salt and pepper
Wash the fish fillets, dab dry and cut in half. Season fillets with salt and pepper. Heat 2 tablespoons of oil in a frying pan, fry the fish on each side over medium heat for about 2 minutes. Serve with the kohlrabi potato tartar. Sprinkle with pepper, garnish with dill and lemon