Cut the kohlrabi and carrots into small pieces, blanch them in the vegetable stock for about 5 minutes, drain the stock again and put the vegetables aside.
Dice the onion and sauté in a little oil. Add the minced meat and pressed garlic cloves and season. Fry until crumbly. Put half of the vegetables in a greased baking dish. Spread the minced meat on top and cover with the remaining vegetables. Mix the cream, egg and cheese and pour over the casserole.
Bake in a preheated oven at 180 degrees for approx. 20 minutes.