In same skillet, heat remaining 1/4 cup olive oil over medium-low heat. Cook onions in oil about 10 minutes, stirring occasionally, until very tender. Add garlic and cook 30 seconds; add celery and cook 2 to 3 minutes. Add tomatoes; cook and stir 2 minutes. Add cooked eggplant, 1/2 teaspoon salt and the pepper; heat to a slow simmer. Cover; cook 20 minutes. Stir in parsley.