Peel, wash and cut the carrots into large pieces. Peel and quarter 4 onions. Wash and quarter apples. Wash and halve the tomatoes. Wash the legs and put them in a wide roasting pan. Add apples, onions, tomatoes, carrots, 4 bay leaves, 10 juniper berries, peppercorns, soy sauce and 3 tsp salt.
Add water until the legs are just covered with it. Bring to the boil, with the lid slightly open, cook for about 1 1/2 hours over a low to medium heat.
Meanwhile peel and chop 3 onions. Clean, wash and quarter the red cabbage, cut out the stalk. Cut red cabbage into fine strips. Cut apple rings into pieces. Heat the lard in a large pot, fry the onions in it until transparent, add the apple rings, 3 bay leaves and 8 juniper berries.
Sprinkle with 2 tablespoons of sugar, let it caramelize slightly, add red cabbage. Steam while stirring, season with salt and pepper. Deglaze with elderberry juice, bring to the boil, cover and stew for about 1 1/2 hours.
Stir several times. Then season to taste with salt, pepper and sugar.
Remove the goose legs from the stock and place them next to each other on a fat pan. Roast in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 1 1/4 hours. Pour the stock through a sieve into a wide pot and degrease.
Bring the stock to the boil and simmer openly for about 1 1/2 hours.
Peel, wash and roughly dice the potatoes and sweet potatoes and cook them in boiling salted water for about 30 minutes. In the meantime mix honey and cinnamon. Take goose legs out of the oven and brush with honey-cinnamon mixture.
Continue frying at the same temperature for about 15 minutes.
Heat milk and 75 g butter. Drain the potatoes, mash them coarsely with a potato masher, while letting the milk-butter mixture run in, season to taste with salt and nutmeg. Place in an ovenproof dish and spread 25 g butter in flakes on top.
Take the legs out of the oven, cover them and let them rest for about 10 minutes.
Increase oven temperature to (electric cooker: 200 °C/ circulating air: 175 °C/ gas: see manufacturer). Bake the puree in the oven for approx. 10 minutes. Stir starch and 5 tbsp. water until smooth. Stir the starch into the boiling broth, bring to the boil and simmer for 2-3 minutes.
Season the sauce with salt, pepper and sugar.
Meanwhile wash parsley, shake dry and chop finely. Arrange red cabbage and goose legs with some sauce on a plate. Garnish with apple wedges if desired. Remove the purée from the oven, arrange in a bowl and sprinkle with parsley.
Add the rest of the sauce.