Soak rice and Urad dal separately for 6-8 hrs.

After being soaked well, make a fine paste of Urad dal and rice. Mix well.

Now ferment it for another 6-8. Hrs.

Now take 2 big spoon of batter in a small vessel and add salt and soda bicarb and mix well. Now in an idli mould grease it with butter, add in each mould one tbsp of batter.

Allow it to steam for 10 mins.

Remove an serve.