Soak the thenai and green moong dal for 4-5 hours. Since i made for breakfast, i kept it overnight.
Drain the water and grind it into a fine paste along with red chili and ginger. You can grind the curry leaves along with this too.
Add salt, asafoetida and curry leaves. Chop the onion finely and add it to the batter. Check for consistency. Let it be like a dosa batter. If you want little thick pesarattu then bring it to idli batter consistency.
Heat a tawa and pour a ladle full of batter to this and spread this in a circular motion like how we do for dosa. Drizzle with few drops of oil.
Let it cook on one side. Flip on the other side and cook for a minute.
Repeat the same procedure for the rest of the batter.
Serve immediately. We had with Kara Chutney.