Preheat the oven to 400ºF.
Wash the pork knuckles and pat them dry. Rub with salt and pepper. Halve the onion.
In a shallow and wide oven-friendly dish, put 3 tablespoons water. Add the sauerkraut, laying the pork knuckles on top. Sprinkle the onion and seasonings evenly.
Place a lid on the pot and bake for about 2 hours. Remove the dish from the oven and turn on the grill. Place the pork knuckles on the grill for another 20 minutes to get a crispier texture.
Serve along side salted potatoes or mashed potatoes.