Remove the outer leaves from the Brussels sprouts and clean them. Bring the Brussels sprouts to the boil in a saucepan with water and a little salt (cook for about 15 minutes, it should still be firm to the bite). Peel the onions, carrots and possibly some celery and cut into cubes. Chop the garlic and chilli pepper into small pieces. Also cut the ready-to-eat chestnuts, plums and leek into small pieces.
When the Brussels sprouts are cooked firm to the bite, add them to the ingredients in the pan. Season again to taste, place in a baking dish and sprinkle with the cheese. Bake at 200 degrees for about 15 minutes until the cheese has turned a nice golden brown.