Heat 1 Tbsp of oil in a flat pan.
Add mustard seeds and cumin seeds , once it starts to splutter add cashews
Add Chana Dal and urad dal and saute till cashews and dals turns light golden brown.
Now add in chopped green chilly and curry leaves and mix .
To this add regular rava / semolina and fry on a medium heat for 2 minutes.
Add ragi flour and continue to roast on a medium heat for 3-4 minutes.
Turn off the heat / stove. Remove pan from the stove and set aside for the mixture to cool down.
After cooling , add in salt , coriander leaves and grated carrot.
Mix well everything .
Add curds and water , stir and mix well , so that there are no lumps.
Keep it covered aside for minimum 10 minutes or more to rest .
Whilst , keep water for boiling to steam idlis . Also grease idli plates with oil and set aside.
After 10-15 minutes, ragi and rava would have absorbed water and batter would be very tight.
Add 1/4- 1/3 cup of curds and 1 - 2 tbsp of water if needed and mix well everything to a Idli batter consistency.
Place ladle full of idli batter on each section of greased idli plates/ molds , tap the molds to level the batter.
Now place the stacked idli plates into a steamer and steam for 10 -12 minutes only. Give standing time of minimum 5 minutes before remove idli's from plates. Alternatively you can cook idli in a pressure cooker without closing pressure (weight) .
Remove Idli plate from steamer , wet the base of idli plate with cold water and remove idli's. Serve Idli hot with Tomato Chutney or Bombay Saagu.