Peel and finely dice the onion and garlic. Wash the chilli and chop finely. Heat oil in a pan. Sauté onion, garlic and chili for about 5 minutes at medium heat. Add the minced meat and fry until crispy brown.
Deglaze with canned tomatoes. Boil up the minced meat mixture while stirring, chopping the tomatoes slightly. Stir in tomato paste. Season with vegetable stock, sugar, salt and bay leaf. Let it boil down for about 8 minutes.
Let it cool down a little. Remove laurel. Meanwhile peel the kohlrabi and cut into slices of about 3 mm thickness. Mix crème fraîche with egg and milk until smooth, season with nutmeg, salt and pepper. Coarsely grate the Gouda.
Wash, clean and slice the tomatoes. First put 1/3 of the chopped tomato mixture into a greased casserole dish. Layer 1/3 kohlrabi slices and 1/3 minced meat alternately in the dish. On the last layer of minced meat, add the crème fraîche mixture.
Finish with the last layer of kohlrabi. Cover with tomato slices and sprinkle with Gouda. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 50 minutes.
Garnish with rosemary. Goes well with baguette.