Peel the tomatoes and puree them in a blender or food processor. Remove the eggplant flesh from the skin with a fork; discard the skin, and coarsely chop the flesh.
Heat the olive oil in a large nonreactive skillet. Add the onion and cook over high heat, stirring frequently, until softened and lightly browned around the edges, 3 to 5 minutes. Stir in the cumin and turmeric to lightly coat the onion. Add the tomato puree, reduce the heat to low and simmer, covered, until slightly thickened, 12 to 15 minutes. Stir in a little water if the sauce is too thick. Add the eggplant, sugar, 1 teaspoon salt and a pinch of cayenne. Cover and cook over low heat for 10 more minutes. Season with salt and cayenne, garnish with cilantro and serve with lemon wedges.
The eggplant can be refrigerated for 1 day. Rewarm before serving.
One Serving Calories 178 kcal, Protein 6 gm, Carbohydrate 34 gm, Cholesterol 0, Total Fat 4.8 gm, Saturated Fat .6 gm.