Wash and Soak rice and dal separately, Soak them in water separately for 4 to 6 hours. CHECK NOTES.
Once they are soaked, grind them separately by adding little water at a time to a smooth paste. Transfer them to a large container.
Now add in ragi flour and salt. Mix well. Cover and let it ferment overnight.
The next morning, the batter would be risen, fold it well. Add in baking soda and mix well.
Now grease idli moulds and pour ladleful of batter into each mould and place it in a steamer. Steam it for 8 to 10 mins till it is done. Insert a skewer to check.
Remove it and leave it cool for 5 mins, take a spoon, dip it in some water, slide it under the idli, they will just pop out.
Place these idlies in hot case and serve hot with tomato chutney.
Notes
1)This is my little secret trick for soaking rice and dal in 30 mins. I just add some hot water(not boiling) over the dal and rice and leave it for 30 mins. Then i drain them and while grinding i add ice cold water to grind. This is how i did this idli and it came out really soft and good.2)The batter should be thick, not thin or runny.3)Dal and Rice should be ground till it is smooth, a little grit in rice is not a issue, since rice would never grind to a smooth paste in mixie.4)Dont add too much baking soda than mentioned, or it will affect the colour, texture and taste of idli.5)Use a large container when you are fermenting, because my batter risen too much and a little over flowed.6)Dont steam the idli more than 15 mins, or it will dry up.