Peel the onions. Wash the meat. Put goose breast in a cool place again. Put goose legs, 3 onions, 2 bay leaves, peppercorns and 3 teaspoons of salt in plenty of boiling water so that the legs are completely covered.
Bring to the boil covered and simmer for about 1 1/4 hours. Clean, wash and roughly cut the soup vegetables. Clean and clean the mushrooms. For the dumplings, finely dice rolls. Heat the milk, pour over the rolls and let them steep for about 30 minutes.
Finely dice 2 onions. Heat the butter, sauté the onions in it and take it out. Wash parsley, shake dry and chop finely. Add eggs, egg yolk, steamed onion cubes and parsley to the rolls.
Knead everything well and season with salt and pepper. Cut 2 onions into slices. Wash apples and cut them into slices. Season goose breast with salt, pepper and marjoram. Lift the legs out of the stock, measure 750 ml of stock.
Place the goose legs and breast on an oven rack and place in the oven. Put onion, apple slices, soup greens and mushrooms on a fat pan and push them under the grid. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 1 1/4 hours.
After about 45 minutes, deglaze with the measured goose stock. Form small dumplings from the dumpling mixture. Put them in 2 portions in boiling salted water and let them simmer for 12-15 minutes. Dice 1 onion.
Heat clarified butter in a pot and fry onion until transparent. Add red cabbage, 200 ml water, 1 bay leaf, cinnamon, cloves and plum jam. Braise for about 25 minutes, stirring several times. Lift the dumplings out of the water and keep warm.
Take the fat pan out of the oven, pour the frying stock through a sieve, degrease. Bring to the boil, stir in sauce thickener, bring to the boil again. Simmer for 1 minute, season with salt, pepper and sugar. Remove breast from bone and cut open.
Arrange meat, sauce, red cabbage and dumplings. Garnish with marjoram.