Wash the leg and dab dry. Season all around with salt and pepper. Place on a fat pan and pour hot clarified butter over it. Cook in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 1 1/4 hours.
Peel the onions, cut them into slices and spread them around the roast. Cut the gingerbread into small pieces, soak in poultry stock. Pour 1/4 litre of water over the roast after 30 minutes cooking time. In the meantime peel and wash the carrots.
Clean and wash the Brussels sprouts. Cook the sprouts and carrots in boiling salted water for 15-20 minutes, drain. Chop walnuts. Melt sugar in a pan until golden brown. Turn the carrots in it, season with lime juice.
Melt the butter. Toss the walnuts and Brussels sprouts in it. Keep roast warm. Dissolve roast with 200 ml water. Pour through a sieve, boil up with soaked gingerbread and puree. Season to taste with salt and pepper.
Roast, sauce - garnish as you like with cinnamon sticks - and vegetables in portions garnished with lime and parsley. Potato thalers taste good with it.