Mix rice flour with water and make a smooth paste. Boil 1 cup (200 ml) water. Lower the heat and add the rice paste a little at a time. Stir continuously till it is completely mixed with water. Keep aside.
Wash and clean chana dal. Boil it in 1 cup (200 ml) water in pressure cooker for 25 minutes or until soft (reduce heat to medium after 3rd whistle and cook for 20 minutes). Do not open the lid. Allow the cooker to cool naturally.
Add chopped cashew nuts and boil for 5 minutes on medium heat.
Add melted and sieved jaggery and cook for 5 minutes till chana dal is well blended with jaggery.
Add rice paste and stir continuously so that there are no lumps. Adjust with 1-2 tsp melted and sieved jaggery if required.
Cover with a lid and cook again on low to medium heat for 8 minutes. Switch off the heat.
Add thick coconut milk and mix well. Sprinkle cardamom powder. Serve as a dessert.