firstly, in a large mixing bowl soak moong dal and chana dal for atleast 4 - 8 hours.
further, drain off the water and blend to smooth batter. add water if required.
transfer to a large bowl.
add rice flour to get the extra crispiness.
also add salt to taste.
mix the batter well and get to dosa batter consistency. add water if required.
further pour a ladleful of the batter on a hot griddle.
spread it in a circular motion thin circle.
also smear a little finely chopped onions, jeera, ginger - chili and oil over the pessarattu.
press gently, so that the onions stick to dosa.
if the dosa is not cooked from top, flip and cook both sides of dosa.
now mark triangle over dosa to fold in triangle shape.
slowly remove the dosa from ends.
and fold to triangle or shape of your choice.
finally, serve pessarattu with hot uppitu, allam chutney or coconut chutney.