Clean the cabbage and cut out the stalk in a wedge shape. Cook the cabbage in plenty of boiling water for 5-8 minutes, gradually removing 12 leaves. Soak the rolls in cold water.
Cut the thick cabbage ribs flat. Peel and finely chop the onion. Knead minced meat, squeezed out roll, mustard, onion and egg. Season with salt, pepper and paprika. Put 2 cabbage leaves on top of each other.
Form 6 dumplings from the minced meat, place them on the cabbage leaves and roll them up firmly, folding the ends in. Wrap with kitchen string. Heat the oil in a frying pan. Fry the roulades all around. Pour in broth and cook for about 40 minutes.
Wash the parsley, dab dry and chop the leaves coarsely. Peel, wash and possibly chop the potatoes. Cook in boiling salted water for about 20 minutes, drain. Remove the roulades from the roaster and keep warm.
Mix flour in cold water until smooth and thicken the gravy. Season to taste with salt and pepper. Arrange roulades, sauce and boiled potatoes on plates, garnish with parsley.