Wash and capsicums into cubes. Thinly slice the onions and slit the chilies lengthwise.
In a wide pan, add besan/chickpea flour/gram flour and dry roast it until the color changes to a golden brown,take care not to burn the flour. Keep the flame simmer, while roasting
Remove the roasted flour on to a clean plate. Now in the same pan, heat oil given 'Tempering', splutter mustard seeds, add hing and curry leaves.
Next add sliced onions and green chilies, saute until onions translucent.
Next add the cubed capsicums, and saute for a minute or two. To this add red chili powder, coriander powder, turmeric powder. Mix well.
Cover and cook for 3-5 minutes, until the capsicums are half-done. Remove the cover, add salt and 2 tablespoon of water to the curry, mix well and cover and cook for 8-10 minutes.
By this time, capsicums would have cooked well. Now, slowly add the roasted besan/chickpea flour to the subzi and stir well.
Do not add the flour all at once, add it in batches and stir as you add. After adding flour let it cook for another 8-10 minutes in a simmer flame.
It might first look as if the curry is all clumped up together, add 1 or 2 tablespoon of oil to the subzi and mix, as the flour gets crisp, the subzi will separate.
After 5 minutes, remove from heat, garnish with fresh coriander leaves and serve hot with roti or rice.