For the filling, first finely chop the young onions and cut the apples into small cubes. Heat some lard in a pan and sauté the onions with the apples until light. Stir in parsley, remove from heat and let cool.
Meanwhile, dice the bread, add the apple and onion mixture, stir in the eggs and milk and season with salt and pepper. Allow the mixture to set for a good quarter of an hour.
Now wash the duck, pat dry, season inside and out with salt and pepper. Rub the outside with marjoram.
Fill the duck with the prepared mixture and sew the opening with kitchen twine.
Preheat the oven to 200 °C. Pour some water into a suitable roasting pan, put the duck in with the breast side down, put it in the oven and roast for about 15 minutes.
Reduce heat to 170 °C and roast the duck for another 90-100 minutes until crispy, turning once and basting repeatedly.
Pour in some more chicken stock if needed.
Lift out the finished duck and let it rest warm for a few more minutes.
Remove the drippings, degrease the juices, deglaze with a strong shot of sweet wine and let it boil down completely. Pour in some soup and let the sauce boil down again.
Carve the duck and serve with the stuffing on warmed plates. Serve the sauce separately.
If the duck is not really crispy after roasting, simply carve it into four pieces and keep the stuffing warm.