Add the parsnips, onions, celery root and carrots to the pot; cook for about 3 minutes, stirring to coat them in the oil flavored by the meat. Return all the lamb shanks to the pot, then add the wine, bay leaves and 1 teaspoon each of kosher salt and black pepper and the water (use more water as needed to make sure the meat is covered). Let the mixture come to a boil, then reduce the heat to medium-low. Cover the pot tightly with a sheet of aluminum foil, then place the pot lid on top to seal the pot well. Cook for 3 to 3 1/2 hours or until the lamb is almost falling off the bone.