Preheat oven to 200°C. Prepare the stuffing first: Soak the roll (into milk or water), squeeze out the liquid and strain through a sieve. Peel onion, cut finley and sauteé in a bit of butter. Combine the mincemeat with the roll, the egg and the onion, season with parsley, salt and pepper. Allow to cool.
Trim the stalk and the outside leaves from the green cabbage and boil the head in salt water for about 10 minutes. Remove 8 large leaves, rinse in cold water. Trim the tough centre rib of each leaf or beat beat flat. Thinly slice the remaining cabbage head leaves and put into a buttered casserole. Flatten the 8 leaves, salt and pepper. Distribute the minced stuffing into the centre of the cabbage leaves, roll up once, tuck in the sides of the leaves and roll up. Place them onto the sliced cabbage in the casserole, put the bacon slices on top, pour in the soup and bake in the oven for approx. 50 minutes. Whisk sour cream, pour over the stuffed cabbage and bake for further 10 minutes. Season to taste with salt and pepper.