Dry roast the dal in medium flame until it turns golden. The dal should not turn brown. Let the dal cool slightly.Wash the dal and drain well.
In a uruli or heavy bottomed vessel, add ½ tsp ghee and add the dal. Fry for a minute and then add 1 ½ - 2 cups of water.
Cook the dal in medium heat until it has absorbed all the water and is completely cooked, about 20-25 minutes. Mash the dal well.
In a saucepan/kadai, add jaggery and ¼ cup water. Melt the jaggery completely. Strain the jaggery to remove any impurities.
Add jaggery to the cooked dal and mix well. Once it starts to boil, add 2 tsp ghee and mix well.
When it starts to thicken, add medium thick coconut milk, cardamom powder, dry ginger power and mix well. Cook till the payasam thickens.
Remove from heat and add the thick coconut milk. Do not boil after adding thick coconut milk.
In a pan heat ghee and fry the coconut bits and cashews separately until golden. Add to the payasam with the ghee.