How to make Idly Batter/Mavu?

This is how My MIL makes these fluffy pillows called Idlis and eating them with spiced Idli podi and coconut chutney used to be my favorite way of starting the day since it mostly featured only during the breakfast or sometimes dinner.Here is the receipe for real fluffy idly batter......

INGREDIENTS U NEED:
1.Parboiled rice/Puzhungalarisi-4cup
2.Urad dhal-1cup

UTENSIL:
Grinder

METHOD OF PREPARATION:

• Soak the Urad dhal and par boiled rice separately for at least 6-8 hrs. I have used Wet grinder to make my batter but you can do the same with your Blender.
• First In the grinder add the lentil and grind it untill fluffy. You need to keep adding little water now and then since it doubles up in volume when ground. When the batter is smooth , remove and pour it in a large bowl and set it aside. 
• Secondly add the rice in your grinder and grind it well. The batter will not be smooth but little coarse-grained now remove it and add it the grinded urad dhal.
• Add salt, mix well and set aside in the warm place.The next day, after fermenting, stir the batter well and use it to make idlis.

GOES WELL WITH:

   Sambar and chutney