There is no way that a batter thinner than that of dosa consistency can be spread on a plantain leaf! It will ooze outta the leaf and mess up the whole place. The outer cover for the ada should be a soft dough made outta fine rice powder. Mix the rice powder with boiling salt water and prepare a soft dough. This should be spread on the leaf to make the outer cover for the ada. The rest of the recipe looks ok.