Wash and soak Urad dal in a vessel with more than twice its amount.
Wash Idli Rava in water in a separate vessel.
Let it soak for at least 6 hours.
When ready to grind, drain the water from the urad dal and using very little water, grind to a smooth fluffy paste.
I must have used about 1/4 cup of water.
Once it is fluffy and smooth, add the drain water from the rice Rava and add to the mixer.
Pulse it at least a couple of times to make a smooth paste.
Remove the batter to a vessel.
Add salt and mix well. Cover with a lid
Store the batter in a wide vessel and keep it for at least 8 hours or overnight for fermentation
Next morning, when the batter is ready, add baking soda and mix well.
Grease the idli molds with oil and fill the molds to 3/4 of the indents.
Fill the steamer with water and bring to a boil.
Once you fill all the plates, keep them inside the steamer and cover them with a lid.
Steam for 15 minutes.
Once it's done, let it cool for a few minutes.
Remove and serve with a side dish of your choice!