Clean the cabbage and cut out the stalk in a wedge shape. Cook the cabbage in plenty of boiling water for about 8 minutes. Remove 8 leaves bit by bit. Cut the thick ribs flat. Cut the rest of the cabbage into small pieces
Wash and quarter the apples and cut out the core. Cut apples into cubes. Peel and finely chop the onion. Knead minced meat, breadcrumbs, onion, mustard, 1/4 of the apple cubes and egg. Season with salt and pepper. Put two cabbage leaves on top of each other. Form 4 longish dumplings from the minced meat, place them on the cabbage leaves and roll them up tightly. Wrap the dumplings with kitchen string
Heat the oil in a frying pan. Fry the roulades in it all around, take them out. Sauté cabbage in frying fat, add 600 ml water, bring to the boil, stir in stock. Add the roulades and cook covered for about 40 minutes
Peel, wash and chop the potatoes. Cook in boiling salted water for about 20 minutes. Remove the roulades, drain the cabbage and collect the cooking liquid. Season cabbage with salt and pepper, keep warm. Heat oil in a pan, fry remaining apples in it. Add cooking liquid and calvados, bring to the boil, stir in sauce thickener and season to taste with salt and pepper.
Warm the roulades in the sauce. Wash the parsley, dab dry and cut into strips. Drain the potatoes, let them evaporate briefly, sprinkle with the parsley. Arrange roulades, sauce, potatoes and cabbage on plates