1Make cornbread as directed on pouches. Cool completely, about 1 hour.
2In large bowl, crumble cornbread and white bread. In 10-inch skillet, melt butter over medium-high heat. Cook onion and celery in butter, stirring occasionally, until tender. Add to bread mixture in bowl. Stir in eggs. Pour in broth, 1 cup at a time, combining until all bread pieces are moistened.
3Heat oven to 350°F. Spray 12-inch ovenproof cast-iron skillet with cooking spray. Pour stuffing mixture in skillet. Bake about 1 hour or until dry. Serve warm.