Peel the skin of the plantains and cut it into small pieces to fit the mixer jar.
First grind the soaked rice along with water (If you want to grind chillies, add them now).
Then add cut plantains and add more water. Grind it to fine paste (dosa batter consistency).
Transfer it to a container, add onion, jeera, coriander leaves, and salt, mix well.
Now the batter is ready.
To make plantain Dosa:
Heat the greased tava/skillet on medium heat.
Once it is hot enough (to check, sprinkle water on the tava, you should hear a strong sizzling sound), pour a ladle of dosa batter in the center. Spread the batter from the center in a circular motion to make a circle.
Add the oil to the center and around the edges, and cover it with a lid.
Once the dosa turns golden yellow, remove it from the tava and serve hot with coconut chutney or chutney of your choice.
Repeat the same procedure for the remaining batter.
Reduce the heat every time you remove the dosa from the skillet and then increase it. Mix the batter every time you make Dosa. NO NEED TO FERMENT!