Cut the rolls into slices of about 0.5 cm thick. Roast in a pan without fat for about 3 minutes on both sides. Mix sour cream, mustard and 8 tablespoons of water. Clean the savoy cabbage, quarter it and cut it into strips from the stalk. Peel onion and cut into strips.
Heat the fat, add the onion and savoy cabbage, pour on the stock and stew in a closed pot for about 5 minutes. Halve the meat loaf and cut into 16 slices. Place one after the other in 2 layers of bread, savoy cabbage and meat loaf in the greased form (approx. 2 litres capacity). Spread half the sour cream on each. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 20 minutes