Put sago and semolina in a bowl. Wash it and drain the water.
Put yoghurtand water to it. Mix them together. The consistency should be moderate.
Cover it with a lid and keep it to ferment overnight (atleast five hours)
The next day, add salt to it.
Make seasoning. Take oil, put the mustard seeds, as it crackles, put cumin, bengal gram, green chilly, curry leaves, cashew pieces and asafoetida.
Pour it over the batter.
Heat the idly steamer.
Grease the plates if you wish. I usually wash them and use right away.
Add soda to the batter.Give a stir. Adjust the consistency of batter by adding a little water.
Put a ladle full of batter in each cavity.
Keep it in the idly cooker and steam for twenty minutes on medium flame.
The idly should be well cooked.
Remove them after sometime. Serve with chutney, sambar or sago.