Step 1: Heat ghee and roast broken cashew nuts in it, drain the cashews and roast sooji in the same ghee until the flavor emanates. Let it cool for few minutes.
Step 2: Take the roasted sooji, Beaten curds, water, salt and mix well. Keep it aside for 30 minutes.
Step 3: Heat oil, crackle mustard seeds, cumin seeds, pepper, add bengal gram, urad dal, asafoetida, curry leaves, green chilies and fry until the dals get golden brown color.
Step 4: Keep the steamer or the idly cooker on heat; add the tempering, roasted cashews, baking soda to the sooji batter and mix well.
Step 5: Pour batter into idly plates and steam cook for 5-10 minutes. Check for proper cooking with a tooth pick or knife before taking out.
Step 6: Serve hot with coconut chutney.
* Usually grated coconut, carrot, ginger and chopped coriander are used in rava idlies. I did not use them as they de-color on steaming; also pepper and cumin have digestion properties and so i replaced ginger with those.