Scrape and make a slit on one side of the bittergourds and deseed. Rub salt over and inside and set aside for an hour. Wash under running water. Set aside.
To prepare the stuffing, dry roast one cup gram flour in a nonstick pan on low heat till it emits a nice aroma. Remove from heat, transfer into a plate and allow to cool.
Add one chopped onion, two tablespoons chopped fresh coriander leaves, salt,half teaspoon red chilli powder, one fourth teaspoon garam masala powder and one teaspoon carom seeds and mix well.
Stuff this masala mixture into each bittergourd and set aside. Heat oil in pan, add onion and sauté till light golden brown. Add ginger paste, garlic paste and sauté for two minutes.
Add coriander powder, red chilli powder, cumin powder, turmeric powder and mix well. Sauté the masala till it emits a nice aroma. Add the stuffed bittergourds, half a cup of water and salt.
Cover and cook on high heat for three to four minutes. Reduce heat and cook for ten to twelve minutes, stirring gently at regular intervals. Add tamarind juice and mix well.
Cover once again and let it cook for another ten to fifteen minutes till the bittergourds are properly cooked. Serve hot.