In a mixing bowl, add 1 cup of sooji.
Now, in a mixer jar, add 1 medium-sized boiled potato, 1 cup of sour curd, 2 chopped green chilies, 1 inch of ginger, and salt to taste. Without adding water, grind it.
Then add the ground batter into the sooji and mix well. Also, whisk it for 2 minutes so that air particles incorporate into it, making it light and fluffy.
Cover and let the batter rest for 15-20 minutes.
Now, the sooji has puffed up, and the batter has become slightly thick. Add 2-3 tbsp of water and adjust the batter consistency to medium-thick, with a ribbon-like pouring consistency.
In a tadka pan, add oil, mustard seeds, chana dal, urad dal, chopped curry leaves, and asafoetida. Sauté until the dal turns slightly golden brown. Switch off the gas and add the tadka into the idli batter. Also, add coriander leaves and mix well.
Now, add Eno and lemon juice. Mix well.
Grease the idli stand with oil and pour the batter into it. Preheat the steamer for 5 minutes.
Place the idli stand in it and steam the idli for 12-15 minutes on high-medium flame.
The idli is properly steamed; check with a knife. Take out the idli stand from the steamer and let it cool down slightly.
Serve soft and fluffy instant rava idli with peanut chutney.