Take a wide and deep bottomed heavy pan or a pressure cooker. Add in the water, rice, sugar, cardamom powder, and the milk. Let it pressure cook on medium flame for two whistles.
Then switch off the gas and let it cool. After cooling down open the cooker and add a pinch of salt. Mix well.
Heat ghee in a pan and fry cashew and raisins in it and pour it over the payasam.