In a pressure cooker, add dal, sambhar powder, turmeric powder, salt and 3 cups of water.
Cook for 3 whistles cut off heat and let it cool down
Heat a heavy bottom sauce pan over medium heat, add oil.Add split urad dal and mustard seeds wait until they crackle.
Then add asafoetida.
Add the cooked dal and mix well. Simmer for 7 to 10 minutes on medium heat.
Then cut off the heat.
Rinse urad dal and rice in water for 2-3 times.
Soak urad dal, and rice together in a water for 4-5 hours
Drain excess water from soaked urad dal and rice.
Transfer drained dal and rice into large jar of mixer grinder.
Add 1/2 cup water and grind until smooth texture. Gradually add more water (as needed) and grind until smooth and fluffy texture.
Transfer it into a large bowl.
Add salt and mix it well. Batter should not be very thick or very thin.
Cover it with a plate and keep it in warm place about 7 to 8 hours.
Grease idli moulds with oil and pour batter over it.
Place moulds in the steamer. Cover steamer with a lid and steam the idlis for 10 minutes .
Remove idli moulds from the steamer and let them cool for few minutes.
Transfer them to a plate
Serve hot with sambar and coconut chutney in the breakfast.