Heat oil in pan. Now add mustard seed, black gram, bengal gram, dry chili, cumin seeds, black pepper powder, asafoetida powder. Once the mustard stop splattering and the grams are roasted. add this to the idli batter and mix well.
Switch on the rice cooker with 2 to 3 cup of water.
In small tumbler fill the idli batter. Keep this in rice cooker, Cover and steam for 8 to 10 minutes or until cooked. NOTE: if you prick the idli with a tooth pick and pull it will come clean if the idli is cooked.