Chop the onion, tomato, chillies into fine pieces.
In a bowl, mix beaten egg with maida and milk.
Add cooked vermicelli, salt, chilly powder, turmeric powder, onion, tomato, green chilies and chopped coriander leaves. Add enough water to make batter as we do for dosa.
Heat oil in a pan and pour dosa batter and cook until it gets cooked well on both sides.