In a sauce pan add the grated jaggery and add water just upto immersing level. Heat it a bit and take off the heat. Let the jaggery dissolve in the hot water. Later strain it if required and keep aside.
In a pressure cooker add the channa dal and about half cup water just add water upto immersing level and pressure cook for 3-4 whistles. The dal should not be over cooked and mushy.
Now add the jaggery, ginger powder, cardamom powder to the cooked dal and bring to boil. Let it simmer for 2-3 mins.
Add the coconut milk and when it is about to boil take off the heat.
Heat ghee in a pan. Add the coconut peices, cashewnuts and raisins and fry till golden. Pour this over the payasam and mix well.
Serve hot or chilled.