Clean the kohlrabis, putting the small green leaves aside. Peel the kohlrabis and cut them into 8 approx. 1.5 cm wide strips. Cook in boiling salted water for 8-10 minutes. Drain while collecting the cooking water. Let the kohlrabi slices cool down a little. In the meantime, put rice in boiling salted water, cover and let it swell at low heat for 15-20 minutes.
Clean, wash and slice the tomatoes. Put kohlrabi slices on a baking tray, season with salt and pepper and cover each with a slice of ham, a slice of tomato and a slice of cheese. Bake in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 10 minutes. In the meantime, peel and finely dice the onion. Cut kohlrabi and tomato leftovers into small cubes. Finely chop the kohlrabi leaves. Heat the fat in a pot and fry half of the onion in it. Add the diced kohlrabi to the onion and fry for 3-5 minutes at low heat. Shortly before the end of the cooking time, add the tomatoes and chopped kohlrabi leaves and fry. Season with salt and pepper. Add the kohlrabi-tomato mixture to the rice and fold in.
Heat the fat in a pot and fry half of the onion in it. Add the diced kohlrabi to the onion and fry for 3-5 minutes at low heat. Shortly before the end of the cooking time, add the tomatoes and chopped kohlrabi leaves and fry. Season with salt and pepper. Add the kohlrabi-tomato mixture to the rice and fold in. Add the remaining onion to the cooking fat and fry. Deglaze with 200 ml cooking water and bring to the boil. Stir in crème fraiche. Stir starch and 2-3 tablespoons of water until smooth, stir into the sauce and bring to the boil. Season with salt and pepper. Arrange kohlrabi medallions and rice with sauce on plates and serve garnished with chervil as desired
Add the remaining onion to the cooking fat and fry. Deglaze with 200 ml cooking water and bring to the boil. Stir in crème fraiche. Stir starch and 2-3 tablespoons of water until smooth, stir into the sauce and bring to the boil. Season with salt and pepper. Arrange kohlrabi medallions and rice with sauce on plates and serve garnished with chervil as desired