3.5 - 4 cupswaterdepends on how thick/thin batter you like
Instructions
Wash and soak 1 cup urad dal(with methi dana) in a bowl with enough amount of water overnight or 4-6 hours
Wash and soak rice and all the other ingredients except salt in enough water overnight or 4-6 hours
Blend rice,water and salt in a mixer with little water,(this takes around 30 seconds in a vitamix blender) once its nearly done, add the urad dal without any water and blend again (takes around 20 seconds)
You may blend the above in 2 or more batches depending on the capacity of the mixer.
To make idli,keep the batter aside to ferment overnight in a warm place.
To make dosa
To make dosa, I prefer to use this batter fresh or keep it in the fridge straighway.
In a bowl take some amount of batter and add some water to get a thin pouring consistency.You may add salt if required
Once its medium hot,add a ladle of batter and spread it evenly.Cover it with a lid
Let it cook for few minutes ,until rawness dissapear.Flip it and cook on the other side for few mins.
Using a spatula,take out the dosa.
To make idli
Grease idli pans with butter/ghee/oil, poul a ladle of batter in the pan
move the idli rack into a steamer and steam for atleast 12-15 minutes.