Clean the kohlrabis and possibly leave some small middle leaves. Wash and peel the kohlrabi and cut off the upper part as a lid. Hollow out the kohlrabi with a pointed knife or a ball cutter and cook in plenty of boiling salted water for 15-20 minutes. In the meantime soak the rolls in cold water. Chop the kohlrabi pieces.
Wash, clean and halve the tomatoes and remove the seeds. Dice tomato halves. Wash chives, dab dry and cut into fine rolls. Squeeze the rolls. Mix minced meat, roll, egg, salt, pepper and chives, except for one tablespoon for garnishing. Add 125 g kohlrabi pieces and diced tomatoes. Drain the hollowed out kohlrabi and let it cool down a little. Fill the kohlrabi with minced meat mixture and place in an ovenproof dish with the remaining kohlrabi pieces. Put the lid of the kohlrabi also in the dish. Pour on the stock and bake in the preheated oven (electric: 200°C/ gas: level 3) for about 45 minutes.
Add 125 g kohlrabi pieces and diced tomatoes. Drain the hollowed out kohlrabi and let it cool down a little. Fill the kohlrabi with minced meat mixture and place in an ovenproof dish with the remaining kohlrabi pieces. Put the lid of the kohlrabi also in the dish. Pour on the stock and bake in the preheated oven (electric: 200°C/ gas: level 3) for about 45 minutes. In between, ladle the stock over the kohlrabi. Sprinkle the finished kohlrabis with the remaining chives and place the lids on top