Wash the brinjals, trim the stalk slightly but don't cut them. Apply 3-4 cuts/gashes vertically taking care to see that the brinjals remain intact and don't break open. Keep aside

Heat a skillet/tawa and dry roast the chillies, coriander and fenugreek seeds one by one - keep them separate on a plate. Allow to cool until they turn crisp, about 5-7 mins

Grind the roasted chillies, coconut, jaggery and salt without using any water or just about 1-2 tablespoons just to aid grinding. We need a coarse, thick mixture.

To the coarse masala add the roasted coriander and fenugreek seeds and pulse  2-3 times or until well mixed. We still require a reasonably coarse masala. Remove the masala and rinse the grinder with approx 1/4 cup of water and reserve it.

Stuff the ground mixture into the slits of the brinjals and cover them with the rest of the masala and keep aside for 5 mins.

Heat oil for seasoning in a heavy, wide based kadhai and toss in the mustard. When it stops spluttering, add the curry leaves and then add the marinated brinjals in a single layer (don't pile them up on top of each other)

Reduce heat to sim and cover the pan and cook for 2-3 mins. Open and flip sides, add the reserved masala water a few tablespoons at a time and cook covered until the brinjals are tender (and the skins shrivel up). The colour of the masala when cooked on a very low heat will change from orangish brown to a maroonish brown. During the entire process take care to see that the masala or the brinjals don't burn so keep an eye out. Burnt masala will be blackish brown in colour.

Remove from heat and serve hot with rice or chapathis