Using a small melon baller, scoop out the pulp and seeds and discard them.
Bring the 3. 0 cups (710 ml) water to a boil in a 2-quart/liter saucepan and partially cook the melons for 10 minutes.
Remove them with a slotted spoon and plunge them into cold water.
After cooling for 5. 0 minutes, drain and pat them thoroughly dry, inside and out.
Cover and pulse until the nuts are powdered.
Transfer to a bowl and add the turmeric, cayenne or paprika, and enough of the 0. 25 cup (60 ml) yogurt to make a moist stuffing.
Divide the mixture into 8 portions.
Using a butter knife, stuff each bitter melon, handling them carefully to avoid tearing the uncut side.
Heat the 5. 0 tbsp (75 ml) ghee or oil in an 8–9-inch (20–22. 5 cm) frying pan over moderate heat.
When it is hot but not smoking, add the melons in a single layer.
After 2. 0 minutes, reduce the heat slightly.
Remove with a slotted spoon and drain on paper towels. Snip the thread and unwind, removing all loose pieces.
Serve hot and crispy with lime wedges.
Don't Overstuff: It’s tempting to pack in as much cashew filling as possible, but leave a tiny bit of room at the edges. This ensures that when the melon shrinks slightly during frying, the stuffing doesn't burst out and burn in the ghee.
Thread Choice Matters: Use plain white cotton sewing thread. Avoid dyed threads or synthetic blends, as dyes can bleed into the food and synthetics might melt under high heat.