Wash all the bhindi and pat dry on a kitchen towel. Snip off both ends and slice each bhindi into 4 lengthwise so that you get thin shards.
Preheat oven to 200 C.
In a bowl, mix together besan, cornflour, cumin powder, chilli powder, ginger garlic paste, oil and lemon juice to make a smooth paste. Add the bhindi to this and toss with your hands till the paste coats the bhindi.
Line one or two baking trays with aluminium foil and spread all the bhindi out on the trays.
Brush with oil, and bake in a preheated oven at 200 degrees centigrade for 30-35 minutes, turning once in between till they are crisp and golden brown.
Take the tray out of the oven and let rest for 5-7 minutes. Sprinkle with chaat masala. Serve as a side dish or as an appetizer.
Notes
Slice the bhindi thinly lengthwise
Make sure to spread the bhindi out well so that it doesn't overlap. This helps it bake evenly.
The time taken to bake depends on your oven. In my oven it took 30 minutes at 200C. Remember to bake till golden brown.