Prepare the knuckle. Make deep narrow slits in the knuckle with a knife at a distance of about 3-4 cm from each other. Chop 3 cloves of garlic into thin slices and roll them in salt on a saucer. Push the garlic slices as deep as possible into the slits in the meat.
Cook the broth. Cut the onion in half lengthwise, cut 5 cloves of garlic crosswise. Pour the prepared water into a saucepan and bring it to a boil. Put half an onion, garlic, salt and sugar into the water. Add pepper, cardamom and star anise. After a few minutes, when the sugar and salt have completely dissolved, put the knuckle into the water. Bring the water to a boil and cook the knuckle for at least 1 hour until the meat is ready.
Prepare the knuckle for baking. Mix honey and mustard in a container until the mixture is completely homogeneous. Remove the boiled knuckle from the pan onto a plate, let the excess broth drain. Spread the knuckle with a mixture of mustard and honey - about half of the mixture should go on the entire piece. Cut the second half of the onion into large rings and place them on a baking sheet.
Bake the knuckle. Preheat the oven to 200 degrees. Place the pork knuckle on the onion and bake for 10 minutes. Then pour the resulting juice over the meat and keep it in the oven for another 5 minutes.