To a large pot over medium heat, add the butter. Once it is melted, add in the celery and onion, turn the heat to medium low, and cook for 8-10 minutes or until the vegetables are soft, stirring occasionally.
Pour the butter and vegetable mixture into a large bowl, and add the remaining ingredients. Stir well, being careful to not smoosh the bread.
Grease a 9x13 baking dish with non-stick spray and add the stuffing mixture. Cover with foil and bake for 30 minutes, then uncover and bake for an additional 15 minutes. Enjoy!