Remove stems from all herbs. Rough chop the herbs. Toast the walnuts for a few minutes. Place eggs in a bowl. Add baking powder, salt and pepper. Mix well. Add herbs, walnuts, and zereshk to the eggs. Mix well until all nicely incorporated. Warm up a non-stick pan with some oil. Place the egg and herbs mixture in. Cover and cook for about 20 minutes on medium-low. Cut the kuku into four pieces and carefully flip each piece. Cover and cook for another 20 minutes or until kuku is cooked through.