1. Rinse the idli rice and urad dal separately under running water. Soak them separately in enough water for at least 4 hours.

2. Drain the water and grind the urad dal in a mixer grinder until smooth and fluffy. Add water if required while grinding.

3. Transfer the urad dal batter to a bowl and keep it aside.

4. In the same mixer grinder, grind the idli rice to a fine paste. Add water as required while grinding.

5. Transfer the rice batter to the bowl containing the urad dal batter.

6. Add salt to taste and mix well.

7. Cover the bowl and keep it in a warm place for 8-10 hours to ferment.

8. After fermentation, the batter should have risen and doubled in volume.

9. Grease the idli molds with a little oil. Pour the batter into the molds, filling each mold 3/4 full.

10. Steam the idlis in a steamer for 10-12 minutes or until a toothpick inserted in the center comes out clean.

11. Once done, remove the idlis from the molds using a spoon or knife.

12. Serve hot with coconut chutney or sambar.