Hang yogurt in a muslin cloth over the sink and let the whey (water) drip out for about 2 hours. Transfer the thickened yogurt to a bowl and add lemon juice, garlic, 1/2 teaspoon salt and half of the cilantro. Mix thoroughly and set aside. Salt eggplant slices with 1 1/2 teaspoons salt and let drain for about 30 to 45 minutes. Pat dry.
Heat oil in a 10-inch skillet (about 1/4 inch deep) and fry eggplant over medium to high heat until golden brown, about 3 to 4 minutes on each side. Remove and let drain on paper towels. Set aside.
Heat 1 tablespoon oil in a 4-quart saucepan. When hot, add ginger and garlic and saute for 20 seconds. Add chopped onion and saute over medium heat until soft, about 6 to 8 minutes. Add paprika, 1 teaspoon salt and tomatoes; simmer for 30 to 40 minutes, or until the sauce becomes thick and is the consistency of ketchup.
Place eggplant slices in a deep baking tray in a single layer. Generously brush the top of each eggplant slice with the tomato sauce. Mix together cumin, black salt, mango powder and chile flakes, and sprinkle on top of the eggplant slices. Seal the tray tight with aluminum foil. Bake in a preheated oven for 20 minutes at 275 degrees F.
Serve with a dollop of thickened yogurt sauce and a sprinkle of the remaining chopped cilantro on each slice.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.