For the powdered masala: -
In a small pan roast coriander seeds, fennel seeds, fenugreek seeds until they turn golden brown in color
In another pan add oil, nigella seeds, onion puree, turmeric powder, red chili powder, coriander powder, dry mango powder, garam masala, nigella seed powder, prepared masala powder, water.
Mix them together and cook them for 1-2 minutes.
Stuff the prepared masala into the bitter gourd
In another pan add oil, fry them and sprinkle some salt and cook them for 10-15 minutes
Bharwa karela is ready to serve.