Wash chana dal and soak it in the water for 4-5 hours.
Drain water and grind it with sour curd, lemon juice and the required water. Grind it coarsely.
Cover and keep it in a warm place for 5-6 hours to ferment.
Then add salt, ginger-green chilli paste and turmeric powder and mix well.
Now pour 2 cups of water into a pan and heat it on medium flame. Grease steamer plates with oil.
Add eno fruit salt to the batter and stir it for a minute in one direction. The batter is increased to almost double.
Pour it into greased plates and place it into the steamer.
Steam it for 15-20 minutes over medium flame.
After 20 minutes open the lid and take out dhokla mould from the steamer and let it cool for a few minutes.
Cut dhokla pieces and make their chura by hand.
In a pan, roast urad dal, moong dal, chana dal, black pepper and dry red chilli. Then grind it into fine powder.
Add grinded powder and water into a mixing bowl. Mix well.
Heat oil in a pan, add mustard seeds, asafetida, and curry leaves and sauté it. Then add turmeric powder and red chilli powder and mix well.
Then add the dal mixture and mix well.
Add 4 cup water and cook rasa on a medium flame for 10-15 minutes.
Then add salt, lemon juice and garam masala. Mix well.
Garnish with coriander leaves and serve.