1 pound tomatoes, peeled and coarsely chopped, or one 14-ounce can peeled plum tomatoes, coarsely chopped
1/4 cup coarsely chopped flat-leaf parsley
2 tablespoons white wine vinegar
1 tablespoon coarsely chopped mint
1 tablespoon sugar
Freshly ground pepper or a large pinch of ground chile pepper
Put the eggplant in a colander and sprinkle with salt. Let stand for about 30 minutes. Pat dry with paper towels.
Heat the olive oil in a large casserole. Add the onion and cook over moderate heat, stirring, until golden, about 8 minutes. Add the eggplant and cook, stirring, for about 5 minutes. Add the garlic and cook until lightly browned, about 3 minutes. Stir in the tomatoes and their juices along with the parsley, vinegar, mint and sugar. Season with pepper and cook over low heat, stirring occasionally, until the eggplant is soft, 20 to 30 minutes. Let cool, cover and refrigerate for at least 1 hour or overnight. Serve cold.