Put knuckles into boiling water. Boil until there is no more foam.
Put the whole onions with small crosswise cut on top of them. Add carrots, pieces of celery root, garlic, bay leaves, cumin, pepper and salt. Boil for two hours on low heat.
In the meantime, prepare a mixture of spices in beer and honey to grease the meat before baking in the oven and during the baking process: all the spices are crushed and then added to the liquids.
When knuckles are ready, take them out of the pot and put them on the baking pan with vegetable oil.
Cut the skin crosswise and rub with the prepared beer, honey mixture. I also sprinkled knuckles with ground pepper and salt.
Bake in a heated oven at 200 degrees.
When the skin begins to brown, take the it out and rub it again with the mixture and put it back. This process is repeated four times.
The last time the oven is placed on the grill mode, to thoroughly brown the skin.