Spread 2 tablespoons butter evenly on bread slices; place on a baking sheet.
Bake at 350° for 25 minutes or until crisp; cut into 1/2-inch cubes.
Melt 1/2 cup butter in a large skillet over medium-high heat; add onion and celery, and sauté until tender. Add broth; bring to a boil. Pour mixture into a large bowl; stir in bread cubes and cornbread. Cover and let stand 20 minutes.
Fold in corn and remaining ingredients. Spoon into 1 lightly greased 13- x 9-inch baking dish and 1 lightly greased 11- x 7-inch baking dish.
Bake at 350° for 35 minutes or until golden.