Take whole onion and roast it directly on the flame. Keep the flame medium-low.

Keep turning while you roast the onion till skin gets black from all the sides. Make sure to roast on medium-low heat, otherwise skin gets black in color quickly but onion will stay raw from inside.

Once it is blackened from all the sides, remove it from the flame and let it cool to touch.

Once onion cools down remove the outer skin.

And chop the onion.

Take the yogurt in a bowl, whisk it till it gets smooth. Add chopped green chilies, coriander leaves and salt. Mix it and keep it aside.

Add chopped onion with its juice to the yogurt mixture.

Mix it well.

Chill in the fridge for an hour or two before serving