Boil the leeks for about 45 minutes. Once they are ready, rinse them under cold water.
In the bowl of a food processor, grind the leeks, potato and cilantro. Add this mixture to the ground beef along with the breadcrumbs and the spices. Mix very well with wet hand. Cover the bowl and refrigerate for about 30 minutes.
In a large pot , heat up 2 cups of pareve chicken stock. Form your meatballs and arrange them in the pot. Cover and cook on a low fire for about 20 to 25 minutes.