Toss the eggplants with ½ tbsp oil and a pinch of salt and arrange in a single layer on a non-stick rack (you can use a baking sheet, but a rack is more effective in preventing the eggplant from sticking)
Broil on high in the oven for between-10 minutes or until the eggplant is lightly browned and almost tender
Meanwhile, heat half of the 1 tbsp of oil and saute the coriander, cloves, cinnamon and cardamom for about 2-3 minutes until fragrant. Drain and remove from the pan to a blender.
In the same skillet, saute the onions and garlic until browned on the edges. Add this to the blender.
Add the tomatoes to the skillet and toss for a couple of minutes until they begin to soften. Add to the blender along with the mint leaves. Add the turmeric, cayenne and jaggery to the blender as well.
Blend the ingredients, adding a little water, until they make a fairly smooth paste.
Cut the grilled eggplant rings into quarters
Heat the remaining oil in the skillet.
Add the ground masala and stir for a few minutes. Then add the eggplant. Simmer together on low heat, about 10 minutes, adding some water if necessary to keep the sauce slightly fluid. Add the jaggery.
Add salt to taste. Garnish with coriander if desired.
Serve hot with chapatis or rotis.