Wash the yam thoroughly to remove all dirt, peel the skin and chop it into small pieces
Boil the yam pieces in sufficient water
Grind it to a smooth paste using a mixie
You can grind it coarsely if you like to have some texture
Melt the jaggery in little water and strain it to remove any impurities
Soak the sago for half an hour, boil it till it becomes transparent and keep aside
Take a heavy bottomed pan
Add the jaggery syrup, boiled sago and yam paste to this
Add the coconut milk and boil the mixture
Add more water or coconut milk and boil to bring it to your desired consistency
Add the crushed cardamom pods
Heat ghee and roast the cahsews and raisins in a small pan
Add it to the payasam
Switch off and cover it
Let it rest for a few minutes before serving