Measure ragi flour, coconut & Jaggery. Keep it ready. Mash the bananas with a fork and set aside.
Take jaggery in a saucepan & add water till it immersed level. Heat the jaggery until it melts completely. Strain the jaggery water using a strainer to remove impurities. Set aside.
In a vessel, add ragi flour, jaggery water, scrapped coconut, crushed cardamom, and mashed banana. Add water little by little and mix well so that no lumps are formed. The batter should be like regular dosa batter consistency neither too thick nor runny. Finally, add cashews to the mixture and mix well. Set aside.
Heat a dosa tawa, add a ladle of batter to it, and spread it to form a circle. Don't spread too much. Sprinkle ghee or oil. Cook until brown on one side for five minutes and flip the dosa. Cook for a minute and remove from tawa. Repeat the same process for the remaining batter.