Wash and soak the rice and urad dal separately for 3 hours.
Change water couple of times, and grind the rice and urad dal separately. Then make a puree of the tomatoes, add to the ground batter, add salt and grind everything together again.
Have the vegetables chopped and keep it ready.
Heat a Tawa and grease with oil. Pour a ladleful of batter, swirl around to spread as a dosa. Sprinkle the onions, green chillies on top.
Cook on simmer, flip on the other side, cook till onions are browned.
Serve hot with Red Chilli Coconut Chutney