Boiled rice : 500 gm
Uluththam paruppu ( black gram dal ) : 125 gm
Salt : as needed
Cooking soda : ¼ tsp
Method
Soak boiled rice and uluththam paruppu in water for 3 hours.
Grind rice a little coarsely and uluththam paruppu into a soft batter.
Mix both, add salt, stir well and leave it overnight.
In the morning, mix soda and pour batter in the idli plate.
Steam idlis for 10 minutes.