Soak the rava in curds for 5 mins. Add the oats to the curds and keep it for another 5 mins.
Heat oil in a pan, add mustard seeds, urad dal, chana dal, onions, green chilli paste and fry.
Saute well and pour over the soaked rava and oats mixture.
Add salt, coriander leaves and cooking soda, combine well.
Grease the idli moulds and put a cashew piece and grated carrot on the base. Pour the rava and oats mixture over it.
Steam cook for 7 - 10 mins as you do with your regular idlis.
Serve hot with your choice of chutney.