Soak the idli rice or long grain rice overnight. Blend it with little water.
Now blend the coconut and all remaining ingredients (except eggplant) with 1 -2 cup of water.
Mix the coconut mixture with rice batter. Add a little water to get batter consistency.
Slice the eggplants into circles.
Place cast iron skillet over medium heat and drizzle a little oil. As the skillet heats up, dunk the eggplant pieces in the batter and place it over the skillet as close to each other as possible to complete a full circle. Place a cover on top.
After 2-3 minutes, flip the side and add little more oil, and cover the lid and continue to cook for 2-3 minutes.
I used this batter for plain dosa also, If you don't want to make plain dosa use more eggplants or brinjal.