Roast the parippu without oil for 5-6 minutes in a pressure cooker. Wash it well & pressure cook with boiled water. Stir well for 5 minutes & remove from gas.
Melt the jaggery by adding 1 cup water.
Add the melted jaggery to well cooked parippu to a wide pan. Mix well. Add 2 tablespoon ghee to this & mix well.
Add light coconut milk & when it starts boiling add medium thick coconut milk. When this mix evaporates and becomes half add the thick coconut milk.
Fry the cashew nuts & coconut pieces in rest of the ghee & add to payasam. Serve hot.
Notes
The payasam keeps well in the fridge for 2-3 days. Microwave for 1 min, before serving. I used Maggie coconut milk powder to make this payasam. For thick coconut milk use 3-4 tbsp milk powder in 1 cup lukewarm water, for medium thick, use 2-3 tbsp milk powder in 1 cup lukewarm water, for thin, use 1-2 tbsp milk powder in 1 cup lukewarm water.