Wash the fillets and dab dry. Heat oil in a pan and fry the meat in it all around at medium heat for about 15 minutes. Season with salt and pepper. Wash the herbs, dab dry and chop finely. Knead with breadcrumbs, parmesan and egg yolk. Season with salt and pepper.
Peel, wash and slice the carrots. Peel kohlrabi and cut into slices. Peel and finely chop the onion. Heat 25 g butter in a pot and fry the onion in it. Add carrots and kohlrabi and steam briefly. Deglaze with broth and bring to the boil. Cook on low heat for 8-10 minutes. Season with salt and pepper. Remove the fillet from the pan and spread with the herb mixture. Bake in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 10 minutes. For the sauce heat 1/8 litre water and lemon juice. Add sauce powder while stirring and bring to the boil.
Season with salt and pepper. Remove the fillet from the pan and spread with the herb mixture. Bake in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 10 minutes. For the sauce heat 1/8 litre water and lemon juice. Add sauce powder while stirring and bring to the boil. Cut remaining butter into pieces and stir into the sauce over low heat. Cut the fillet into slices and arrange on a plate together with the vegetables. Garnish as desired with basil and chervil and serve