Heat the pan and when the pan is hot enough, pour a ladleful of batter. Spread the batter circularly to make a thick dosa.
Sprinkle chopped onions, green chilies, and coriander leaves over the dosa. Also, spray tbsp of oil over the dosa and along the sides of dosa.
Fry dosa till it turns slightly golden and flips it over.
Fry till onions are nicely fried.
Tasty onion uthappam is ready. Serve hot with any of your favorite chutneys.