For preparing tasty onion dosa, soak raw rice and split black gram separately over night.

Grind it separately in a blender till smooth. Mix both the batters together.

Mix in sour curd, soda bi-carbonate and salt with required water to get a thin batter. Keep it aside for 15 minutes.

Heat 3 tablespoons of oil in a small frying pan. Splutter mustard seeds and then add asafoetida powder.

Then add the onion, curry leaves and green chillies.

Fry till the onion becomes transparent. Allow it to cool and add into the batter.

Heat a tawa and pour a ladle full of the batter and make dosa`s. Fry it on both the sides.

Tasty onion dosa`s are ready. Serve immediately with chutney.