In a small saucepan, bring water to a boil. Turn off the heat and add the grated jaggery, mix well for the jaggery to melt. Cool slightly.
In a medium size bowl, combine ragi flour, rice flour, grated coconut, ground cardamom and salt. Whisk well to combine. Add the slightly cooled jaggery water mixture and whisk well to make a smooth batter. Set aside for 10 minutes.
Batter will thicken as it sits. Add ¼~½ cup water to thin it out. It should have dosa bater consistency.
Heat a nonstick pan, pour 2 ladle full of batter and spread it around into medium size dosas. Batter won't spread like regular dosa batter. So simply pour it into a even and fill in any holes. Drizzle a little oil or ghee over the dosa and cook on medium flame until the dosa is golden and cooked through.
Flip and cook on the other side for another minute. Serve hot and Enjoy!!