Heat oil in a pan.

Add mustard seeds, curry leaves, gram dal and black split dal.

Let it splutter.

Add semolina and salt.

Roast for 1 minute on low flame.

Switch off flame.

Let it cool.

Add curd, baking soda and baking powder in semolina.

Keep for 10 minutes.

Mixture will be little dry, add 2 tbsp water and mix well.

Grease idli moulds with oil.

Pour idli mixture in moulds.

Steam for 10 minutes.

Remove idli from moulds.

Serve with sauce or coconut chutney.