1 Heat the oven to 220°C (200°C in a fan oven), 425°F, gas 7.
2 Rub the knuckles with salt and ground black pepper. Heat the lard in a roasting dish and brown the knuckles on all sides for around 5 minutes. Add the vegetables and fry together briefly. Pour in half of the beer and roast the knuckles for 1 hour on the lower shelf; baste regularly with the juices and add the meat stock.
3 After 1 hour, increase the temperature to 240°C (220°C in a fan oven), 475°F, gas 9. Brush the knuckles with the remaining beer and cook for a further 20 minutes. Switch the oven off and leave the meat in it to rest.
4 Meanwhile, heat the lard for the sauerkraut in a suitably large pot and sauté the onion and bacon until it goes pale. Add the sauerkraut and brown for 5 minutes, breaking it up with a fork in the process.
5 Add the bay leaf, juniper berries and clove. Pour in the wine and the stock or water, and season to taste with salt and ground black pepper. Cover the pot with a lid and leave to cook for 1-1.5 hours, adding more water if necessary.
6 Plate up the knuckles and sauerkraut. Serve with potato dumplings if desired.