Soak channa dal in water for 5 hours. Boil in cooker (1 whistle) and drain the excess water. Heat oil. Fry onion for 2-3 minutes. Add green chillies, ginger, chilly pwd, garam masala, garlic, amchur pwd, chat masala and salt to taste. Fry for two minutes. Remove from fire. Mix chopped coriander leaves.
Spread chana dal over a puri. Spread green and sweet chutney over this. Sprinkle some chopped onion over the chutney. You can add a tsp of chat masala in onion.