Preheat the oven to 400F. Line the baking tray with aluminium foil, spray it with some oil and keep aside.
Wash and dry the bhindi /okra thoroughly using a kitchen/paper towel.
For each Okra, chop off the head and tail and cut it length wise into 2-4 pieces depending on the size of okra. Make sure to cut them equal i.e. 2 or 4 pieces for even cooking.
Transfer the cut Okra onto the lined baking sheet. Add oil, salt and pepper. Toss well so that each okra get well coated.
Spread them evenly and avoid overlapping any okra. Do not overcrowd them as that will result in them being steamed rather than turning crispy. Bake in 2 batches if required.
Bake at 400F for about 15-20 mins or until the okra has turned crispy turning it half way through (time may vary from oven to oven). Make sure not to burn the okra as it will turn bitter in taste.
Now bump up the temperature to 425F and bake for another 5-10 mins until the okra's have crisped up.
Remove from the oven and let it sit on the hot baking sheet for another 5 mins which will help crisp them up further.
Add all the spices into a bowl - coriander powder, red chilli powder, cumin seeds powder, dry mango powder and chaat masala.Mix it and toss it with the crispy okra until every Okra is well coated. Add spice mix to your taste.
Sprinkle some coriander leaves and serve.