Begin by peeling the bitter gourds and removing the seeds if they are tough. Rub them thoroughly with salt and let them sit for at least 30 minutes; this is a crucial step to draw out the natural bitterness.
After 30 minutes, wash them well under cold water and squeeze them firmly to remove any excess moisture. Set them aside to dry.
In a medium pot, combine the soaked chana dal, sliced onion, cubed tomatoes, green chilies, and ginger-garlic paste. Season the mixture with cumin seeds, garam masala, turmeric, red chili powder, and salt. Pour in two glasses of water and set the pot over medium heat.
Cover and simmer until the dal is completely tender and the water has evaporated. Once cooked, let the mixture cool down significantly so it is easy to handle.
Take your prepared bitter gourds and carefully fill the center of each with the cooked lentil mixture. To ensure the delicious filling doesn't spill out during the cooking process, wrap each gourd securely with a piece of clean cotton thread, tying it off at the end.
Heat the ghee or oil in a wide skillet over low flame. Carefully place the stuffed gourds into the pan. It is important to cook them slowly on low heat to ensure they soften and turn a beautiful golden brown without burning. Avoid moving them too much in the beginning; once one side is golden, gently flip them to sear the other sides evenly.
If you have any leftover lentil filling, place it back into a pot and nestle the fried bitter gourds on top. Drizzle about half of the remaining warm oil from the frying pan over the dish. Cover the pot and let it steam on the lowest heat setting for another 2 to 3 minutes. This allows the flavors to meld together perfectly.
Remove the threads before serving if desired, or let your guests do it for the authentic experience. Garnish generously with freshly chopped coriander and serve hot for a meal that is as healthy as it is flavorful.