Boil black chick peas and yam seperately to 3/4th with salt and keep it ready. Do not cook it fully because we need to mix both and cook again. Yam will get mashed if cooked fully.
Add both together and add turmeric powder and chilli powder, mix well.
Grind half of the coconut grated with cumin seeds to a paste.
Add the paste to the curry. Give it a boil and switch it off.
Heat coconut oil in another pan , splutter mustard seeds and add curry leaves and red chilli to it. Now add remaining coconut and fry till its reddish in color . Before its completely reddish, add pepper powder and fry it.
Add the tempering to the curry along with jaggery powder and few drops of coconut oil. mix well and serve!