Take a big bowl and add ragi flour, semolina and yogurt and mix.
Add water and salt and mix well.
Heat oil in a small pan and add urad daal ,cumin and mustar seeds.
When the seeds start crackling then add asafoetida,green chilies,ginger and curry leaves .
Remove from the flame and add the tempering in the ragi batter and mix.
Cover the batter and keep aside for 15 minutes. if the batter become thick after 15 minutes then add few tbsp water to adjust the consistency.
Boil water in the steamer and grease the idli plates with oil.
When the water in the steamer start boiling then add eno in the ragi batter and pour the prepared batter in the idli molds.
Put the mould in the steamer,close lid and steam for about 12-15 minutes on high heat.
Switch off the heat and wait for 5 minutes before opening the steamer.
Now open the steamer lid ,take out the plates and let them rest for 5 minutes.
Now using a wet spoon scoop out the idlis from the mould
Serve hot with sambhar or any chutney of your choice.