Preheat the oven to 425 degree F. Line a baking tray with parchment paper. Rinse & dry the eggplant(s) and place them on the baking tray. Make a long slit going almost ¾ th way through each eggplant and then make 3 slits on each side of the long slit. Spray a layer of olive oil all over the eggplant.
Broil for 25 to 30 minutes, or until the skin starts to char and the eggplant has softened. Allow the eggplant to completely cool down and then using a spoon and knife gently open the eggplant from the middle slit separating the 2 sides of the eggplant. Then scoop out the inner flesh, give it a rough chop and discard the outer skin.
Heat oil in a medium pan and add mustard seeds and allow them to pop. Add turmeric, curry leaves and onions. Cook covered on medium heat for 3-4 minutes.
Add crushed chilies and garlic. Sauté for a min, add half of the scallions and tomatoes. Mix well and cook for 2 mins on medium heat. Add roasted eggplant and Salt. Mix well and cook for 2 minutes. Garnish with remaining scallions and cilantro.