For the cheese béchamel melt the fat in a pot. Dust with flour and sweat it while stirring. Gradually add stock and milk while stirring. Simmer for 5 minutes. Add cheese and let it melt in the sauce.
Season to taste with salt, pepper and nutmeg. Cut the bread roll into slices. Halve the meat loaf slices once. Alternate slices of bread with the meat loaf in an ovenproof dish. Pour the sauce over it.
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 35-40 minutes. In the meantime, peel onions and cut into rings. Heat oil in a pan and fry onion rings in it.
Wash the chives, dab dry, put some stalks aside. Cut the rest into fine rolls. About 10 minutes before the end of the cooking time, spread onion rings on the casserole. Sprinkle with chives and garnish before serving.
Salad tastes good with it.