Ingredients

　　3 1/2 pounds onions, halved lengthwise and cut crosswise into 1/2-inch-thick slices

　　1/4 cup olive oil

　　7 celery ribs, cut diagonally into 1/2-inch-thick slices

　　In a large heavy skillet cook the onions in the oil, covered, over moderately low heat, stirring occasionally, for 45 minutes. Season the onions with salt and pepper and cook them, uncovered, over moderately high heat, stirring occasionally, for 30 minutes, or until they are tender and beginning to turn golden. Add the celery and cook the mixture, stirring, for 5 minutes, or until the celery is crisp-tender. Serves 6.