Preheat oven to 450 degrees. Char over a gas flame, grill, or broil the eggplants until the skins are charred and blistered. Transfer to baking pan and roast for 30 minutes or until soft. Remove from oven and cool. Toast cumin and coriander seeds until aromatic and grind in a spice grinder (or toast spices already ground).
Heat oil in a small skillet over moderate heat. Add onion and saute until tender. Add garlic and ginger and saute a few seconds to release the aroma. Add turmeric, ground toasted cumin and coriander and salt and saute another minute just to release the aroma.
Cut stem ends of eggplants and peel skin. Set eggplant in food processor and puree until coarse. Add onion and spice mixture and puree. Transfer to serving bowl and stir in lime and yogurt and jalapeno. Right before serving dust eggplant puree with chopped cilantro and mint. Serve with toasted pita triangles or fresh vegetables or crackers.