In a large mixing bowl, combine besan, turmeric powder, red chilli powder, cumin seeds, and salt.
Gradually add water while whisking continuously to form a smooth lump-free batter.
Let the batter rest for 5 minutes so the besan absorbs the moisture and develops a better texture.
Add chopped onion, grated carrot, capsicum, green chilli, and coriander leaves. Mix well.
Heat a non-stick pan or tawa over medium heat and lightly grease it with oil.
Pour a ladleful of batter onto the hot pan and spread gently into a thin circular chilla.
Cook for 2–3 minutes until the edges begin to lift and the bottom turns golden brown.
Flip carefully and cook the other side for another 2 minutes until fully cooked.
Repeat with the remaining batter.
Serve hot with mint chutney, coriander chutney, yogurt, or tomato ketchup.