Boil the lentils till done. Strain and set aside.
Drain the rice and grind the rice with one cup of water till smooth. If your blender is like mine not grinding smooth, then strain the mixture and set aside.
Add 1/2 cup water to the coconut and grind. Extract the first milk and set aside.
Put back the squeezed coconut, add 4 cups of water and blend till smooth. Strain out the thin coconut milk.
Mix the ground rice mixture and thin coconut milk and start boiling the mixture.
As it heats, add the boiled lentils and chopped plaintains and cook till the mixture thickens and the plaintains are soft.
Add in the first coconut milk, sugar, cardamom and salt and cook for another couple of minutes.
Serve warm.