In a wide bowl add the idli rice, toor dal and wash it well.
Add water to this and soak this for 4 hours or overnight.
I usually add the red chili also while soaking so that it will be easy to grind.
After 4 hours, drain the water and grind this into a smooth paste.
Add necessary water and bring it to a consistency of dosa batter.
Now add salt, asafoetida and finely chopped curry leaves.
If you are adding onions, finely chop 1 onion and add to the batter.
Mix well. You can make dosa immediately.
If you want to ferment, just ferment it for 2 hours.
Heat a dosa tawa and take one ladle full of dosa batter.
Spread this into a thin dosai.
Drizzle ½ tsp of oil.
Let this cook on one side.
Flip the dosa and cook for few seconds.
Take out from the tawa. Crispy Toor dal dosa is ready.
Serve hot. Repeat this for the rest of the batter.