Soak the rice and gram overnight or for at least 6 hours.
Drain and grind the rice and gram along with green chillies, cumin seeds, ginger and salt and enough water to a smooth paste.
You can start making Pesarattu soon after grinding. Leaving it for an hour will help making it more crisp.
Mix the onion and corinader together and keep aside.
Heat the tawa/griddle.
When the tawa/griddle is hot, reduce the heat and pour a ladleful of batter into the centre and spread quickly towards the edges in a circular motion, till the batter is evenly spread .
Sprinkle the onion-coriander mixture on top.
Increase the heat and when you see a change of colour in the batter, drizzle a teaspoon of clarified butter along its sides and centre.
Scrape off the excess batter off the surface, using a spatula, to get a thin Pesarattu.
The Pesarattu should look like this after the excess batter has been scraped off.
When the Pesarattu turns golden brown, carefully loosen the edges and remove from the griddle and serve hot with Coconut chutney or any chutney of your choice.