Preheat oven to 400°F. Wrap garlic cloves in aluminum foil. Prick eggplant all over. On a baking sheet roast garlic and eggplant in middle of oven 30 minutes, or until garlic is tender. Transfer garlic to a plate and continue to roast eggplant until blackened and collapsed, about 45 minutes more. While eggplant is roasting, in a small skillet dry-roast seeds over moderate heat, shaking the skillet, until fragrant, being careful not to burn them, and in a mortar with a pestle, an electric spice grinder, or a cleaned coffee grinder grind fine. With a large spoon scrape eggplant flesh from skin, discarding skin, and chop coarse. Peel garlic cloves and with flat side of a knife mash to paste. In a bowl stir together eggplant, garlic paste, spice mixture, tomatoes, fresh coriander, lemon juice, oil, gingerroot, paprika, salt, and 2 tablespoons mint until combined well. Salad may be made 2 days ahead and kept chilled, covered. Sprinkle salad with remaining 2 tablespoons mint and serve at room temperature.