- Rinse and soak urad dal for 6hrs. 
- Soak idly rava for 6 hrs. 
- Take dal in a blender or add full dal to the wet grinder and blend it smoothly by adding little by little water when ever it required. 
- Transfer the batter to the large vessel and add salt. 
- Drain off the water and also squeeze the excess water from the rava with hands and keep aside. Make sure that there is no water in the rava.  
- Add idly rava to the urad dal batter. 
 
 
- Mix the rava and urad dal batter nicely. 
- Keep the batter in a warm place and let it rest for 6-8 hrs or until it ferments well without becoming sour.  If you are living in a cool place, place the batter in the oven and turn on the light.  
- A well fermented batter rises well and looks fluffy.