Cut the skin of the pork knuckle into a diamond shape. Season the knuckles.
Put 1/4 liter of water in a saucepan, place the knuckle in it and fry it on the middle bar in the oven for approx. 2 1/2 hours. During the entire cooking time, pour the frying stock over the knuckles every 15 minutes.
Quarter the onion and add to the knuckles after approx. 1 1/2 hours. Increase the temperature to 250 ° C 30 minutes before the end of the cooking time. Brush the meat repeatedly with beer and finish cooking. Keep the finished knuckles warm.
Remove the frying stock from the pot with a little water, pour through a sieve into the pot, bring to the boil once, season to taste and serve unbound with the knuckles.
Side dishes: bread dumplings, cucumber salad or cabbage salad.