Preheat the oven to 175 degrees C (350 degrees F). Puncture eggplants with a fork, and place on a baking tin. Bake for 1 1/2 hours, or until soft, turning occasionally. Cool, then peel and dice.
In a large bowl, stir together the garlic, olive oil, vinegar, sugar, parsley, oregano, basil, salt and pepper. Add the diced eggplant, and stir to coat. Refrigerate for at least 2 hours before serving to marinate.