Set the batter aside in a warm place for at least 6 to 12 hrs until the batter ferments and rise well. Sometimes it may take up to 18 hours depending on the weather and temperature.A well fermented batter will yield good soft idli. The batter must rise and look fluffy but not turn sour.

Mix the batter gently a few times. do not over do as the aerated batter will turn flat. Fill the moulds with batter.
When the water begins to bubble and steam up, place the stand in the steamer.
Cover and steam for exactly 10 mins on a medium high flame.

After 2 mins, remove the idli stand. Set aside to cool down for 2 to 3 mins. When cooled, the idli must not be wet on top.
With the help of a spoon remove them to a plate.

For Sambhar:Wash toor dal a few times in cooker or pot until the water runs clear.

Pour 2 cups water & pressure cook on a medium heat for ten minutes depending on the brand of cooker. The dal needs to be cooked till smooth.

When the pressure goes off, mash the dal to smooth. The dal needs to be very smooth otherwise it doesn’t taste good.Pour the tamarind pulp, filter if you desire.
Add smooth dal, mix well to blend the dal with water. Bring it to a boil. Check if there is enough salt & sourness. If needed add more.

Meanwhile, heat another pan with oil or ghee.
Add mustard, cumin & methi. When they begin to sizzle, add curry leaves, broken red chilli. When the leaves turn crisp, off the heat add hing. Add chopped onions,roast and add tomatoes purée,sauté well.You can also add 1/8 to 1/4 tsp of sambhar powder to the hot pan.Add some sambhar to the pan.

Quickly pour this seasoning to the sambar. Stir well. Simmer for 2 to 3 minutes for the sambhar to become flavourful. We usually pour 2 to 3 ladles of sambhar to the tempering pan as the aroma of the tempering will be great this way.Serve hot with Idlis.