Heat 2 tsp ghee or oil in a pan.
Add rava in it and roast in the ghee or oil till they become aromatic and change color.
Keep on stirring while when you are roasting them.
Keep the roasted rava in a bowl keep aside.
Take a pan add 2 tsp oil in it and heat it. Add mustard seeds, chana dal, curry leaves and asafoetida. Fry till the chana dal become golden.
Add this whole mixture to the roasted rava. Add yogurt along with chopped ginger, green chilies and salt.
Add water as required to make the batter which is neither thin nor thick.
Keep aside and cover it for 20-30 minutes.
You can add water to give the batter a medium consistency.
Heat water in a steamer, or pressure cooker, add baking soda in the batter and mix it well.
Pour the rava idli batter in greased idli moulds.
Place the idli stand in the steamer or pressure cooker steam the rava idlis for 10-12 minutes or more till a toothpick inserted in the idlis come out clean.
Remove the rava idlis from the mould and serve the steaming hot rava idlis.
Enjoy these rava idlis with your favorite chutney.