For optimal food safety and even doneness, the USDA recommends cooking stuffing separately. Heat oven to 350°F. Spray 13x9-inch (3-quart) glass baking dish with cooking spray.
In 4-quart Dutch oven, melt butter over medium-high heat. Cook celery and onion in butter 4 to 6 minutes, stirring occasionally, until tender. Add remaining ingredients; stir gently to mix well. Spoon into baking dish.
Cover with foil; bake 25 minutes. Remove foil; bake 10 to 15 minutes longer or until center is hot and edges are beginning to brown.