Dry roast dhuli moong dal till lightly browned. Boil the sweet potatoes. Drain, cool, peel and mash.
Add two cups of hot water to the roasted dal and cook till done. Drain any excess water.
Heat three tablespoons of ghee in a pan and add the cooked dal and sauté. Add rice flour and jaggery. Mix and cook stirring continuously till the jaggery melts completely. Add mashed sweet potatoes and mix. Continue to cook till dry.
Transfer into a bowl and set aside to cool. Add green cardamom powder and mix.
Divide the mixture into equal portions and shape them into small cylindrical shaped pulis.
Heat sufficient ghee in a kadai and deep fry the pulis for one to two minutes or till golden brown. Drain and place on absorbent paper.