Clean and wash the Brussels sprouts. Steam covered in approx. 3/8 l boiling salted water for approx. 15 minutes
Dice the ham. Grate cheese. Drain the brussels sprouts and collect the vegetable water. Heat the fat. Sweat flour in it while stirring. Stir in milk and vegetable water. Bring to the boil and dissolve the stock in it. Simmer for about 5 minutes, stirring frequently. Melt 100 g cheese in it. Season to taste with salt, pepper and nutmeg
Put the sprouts and ham in a greased casserole dish. Pour sauce over it. Sprinkle with the remaining cheese. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C / gas: level 3) for approx. 40 minutes until golden brown. Served with: Boiled potatoes