1. HEAT oven to 375°F. Spray 13 x 9-inch (3-quart) baking dish or pan with no-stick cooking spray. Melt butter in large skillet over medium-high heat. Add onions and celery; cook until tender, stirring occasionally. 2. COMBINE onion mixture with all remaining ingredients in large bowl; mix well. Spoon into prepared baking dish. 3. BAKE 45 to 50 minutes or until golden brown.