Make tiny slits all over the eggplants and roast them in a 400 degree oven for 20-25 mins till the skin starts to char on all sides. Peel the eggplants, mash it to a pulp and set aside.
Heat oil in a large pan and add in cumin seeds. As soon as they begin to sizzle, add in chopped ginger and onions, and fry for 2-3 minutes on medium-high heat till onions start to soften and lightly brown.
Add in spices and chopped tomatoes, and fry for a few minutes till tomatoes start to pulp and give out oil along the sides. Season with salt, and mix in the mashed eggplant. Stir to mix well and cook covered on low heat for 3-4 minutes.
Sprinkle garam masala on top and garnish with fresh cilantro leaves. Serve hot with a side of rotis.