1.Wash black gram thoroughly with water.
2.Add methi seed to the black gram and soak the mix for 4 hours.
3.Grind the soaked mix into a smooth batter.
4.Add ragi flour and salt to the batter and mix well.
5.Leave the batter to ferment for 3 hours.
6.Grease the idli mould with oil.
7.Pour batter in to the idli mould and steam for 15 to 20 minutes.
Serve hot with sambar and chutney.
Note: You can add baking soda instead of methi seed. In which case, add after grinding the batter.