Heat oil in a pan and temper with mustard seeds. After it stops spluttering, add the urad dal, green chili (opt) and asafoetida. Saute for a few seconds.
Add the semolina and fry on a medium flame for a minute or till you get a nice aroma coming through. Keep aside to cool down.
Add the fried semolina to the powdered oats. To it add the fried onions, chopped mint leaves, salt to taste and red chili flakes (opt). Combine everything well.
Add required quantity of buttermilk to make a batter. Just before steaming, add the eno fruit salt and some more water if needed and mix well.
Ladle the batter into greased idli moulds and steam for 12-15 minutes. When cool enough to handle, demould them and serve them with coconut chutney and sambar.
