Wash the legs of duck, dab dry and rub with salt and pepper. Roast the legs in a roaster in a preheated oven (electric cooker: 200°C/ gas: level 3) for about 1 1/4 hours.
After 30 minutes frying time, pour on half of the juice and half of the port wine and 1/8 litre of water. Gradually add the remaining liquid, pouring the stock over the legs. Wash the potatoes and cook in boiling salted water for 20 minutes.
Peel carrots. Clean the leek. Wash the vegetables and cut them into thin, five centimetre long sticks. Dice rolls. Heat a tablespoon of fat. Fry the bread roll cubes in it until golden brown. Drain the potatoes, peel them and press them through a potato ricer.
Knead the potatoes, 1/3 of the vegetable strips, eggs, flour and starch, season with salt, pepper and nutmeg and divide into twelve equally sized pieces. Place bread cubes on the middle of the pieces and form into dumplings with floured hands.
Cook the dumplings in lightly boiling salted water for 15 minutes. Cook the remaining vegetable strips in the remaining heated fat for five minutes, turning several times, and season. Remove duck legs from the stock and keep warm.
Mix stock, gravy and sauce thickener, bring to the boil and season the sauce to taste. Remove the dumplings from the water. Arrange legs, vegetables, dumplings and some sauce on plates. Serve garnished with parsley.