Wash and soak urad dal in water for three hours. Grind it to a smooth batter by adding little  amount of water.

Renove the batter in a bowl. Mix the ragi flour and salt to it.  Keep it in a warm place for eight hours to ferment. Ideally, it is good to keep overnight.

Next day, take the idli stand and wash the plates. Add a spoonful of batter in each mould. Heat the pressure cooker or the idli cooker and keep them to steam on a medium flame for fifteen to twenty minutes. Once done, remove from heat and serve  with coconut chutney.