Preheat oven to 475 degrees. Prick eggplants and roast for 35-40 minutes until colapsed and wrinkled. Let cool.
Meanwhile, heat oil in a small pan and add onion over medium heat and cook 3-4 minutes. Add next 6 ingredients and saute until onions are soft and mixture is fragrant.
Pour mixture in food processor and cool slightly. Add yogurt, cilantro and tomato paste and process until smooth.
Remove the pulp from the roasted eggplant and put into processor and process until smooth. Add lemon juice and salt and pepper to taste. Process again for 30 seconds. Serve hot, cold or room temp with pita chips.