In a frying pan add cumin seeds, coriander seeds, fennel seeds, red chili buttons, nigella seeds, black mustard seeds and dry roast until fragrant. Take out in a bowl and let it cool.
In a spice mixer add roasted spices and grind well. Set aside and reserve for later use.
Peel and deseeded bitter gourds (Karela).
Place the peels in a bowl, add salt and mix well.
In a small frying pan heat mustard oil, squeeze bitter gourd peels to remove the excess water and add in frying pan. Fry until turns brown and set aside.
Place the bitter gourds in a bowl containing sieve, sprinkle salt and rub them. Leave it for 30 minutes.
In a wok add mustard oil, onion, fry until translucent. Add raw mango and mix well.
Add ginger garlic and mix well.
Add green chilies, fresh coriander and mix well.
Add red chilli powder, salt, turmeric powder and mix well.
Add 2-3 tbs of grounded spice mix and mix well.
Add fried bitter gourd peels, mix well and set aside.
Wash bitter gourd with water, squeeze out excess water and pat dry.
Stuff prepared stuffing in bitter gourds and tied them with kitchen thread, set aside.
In a wok heat mustard oil, add stuffed bitter gourds, cover and cook on low flame for 6-8 minutes. Remove the lid and turns the side of bitter gourds.
Sprinkle left over grounded masala over the bitter gourds, cover and cook again on low flame for 6-8 minutes
Open the lid and cook for 2-3 minutes on high flame or until fully tender
Serve stuffed karela with salad and chapati.