1. Preheat the oven to 350°F (180°C). Cut the eggplants in half lengthwise and score the flesh of each in a crosshatch pattern with a sharp knife.
2. Brush the flesh with 4 tbsp of the oil. Place, cut sides up, in a roasting pan. Bake in the oven for 30–35 minutes, or until tender.
3. Let the eggplants cool. Scoop out and reserve the flesh, leaving a ¼ in (6mm) shell, being careful not to split the skins. Place on a serving platter.
4. Heat the remaining 2 tbsp of the oil in a large, heavy-bottomed saucepan over medium heat. Add the onion and garlic and cook, stirring occasionally, about 5 minutes until softened. Add the coriander, cumin, turmeric, and cardamom and stir about 1 minute, until fragrant.
5. Stir in the tomatoes and their juices and bring to a boil. Reduce the heat and simmer for about 30 minutes, stirring occasionally, until reduced and thickened. Stir in the reserved eggplant flesh and raisins and cook for 10 minutes more. Let cool, then stir in the cilantro, mint, and parsley.
6. Spoon the mixture into the eggplant shells, and refrigerate for at least 1 day before serving.