Wash the potatoes and cook in boiling water for 20 minutes. Clean and wash the Brussels sprouts, cut them in half if necessary and cook them covered in boiling salted water for about 15 minutes. Drain the sprouts. Drain potatoes, rinse, peel and slice. Melt the fat. Add flour and sweat in it. Add vegetable stock and milk while stirring constantly, bring to the boil and simmer for 5 minutes.
Season with salt, pepper and nutmeg. Grate cheese. Wash meat, dab dry and cut into 8 thin slices. Layer potatoes, Brussels sprouts and cured pork loin in a greased casserole dish (26 cm Ø). Pour béchamel sauce over it and sprinkle with cheese. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 20 minutes