In a bowl add sliced onions, spices, coriander leaves, curry leaves, mint leaves and combine well.
To this add besan, rice flour and combine until well coated.
Add 2-3 tbsp water or a little more to make the batter stick to onions. Make sure the batter is thick.
Heat up the waffle iron, brush it with oil, pour the batter, apply little oil on top, close and roast for 1 cycle.
Turn the waffle and roast for a few more mins to make it crispy. Serve hot with ketchup.