Preheat oven to 400 degrees F. Coat a 2-quart baking dish with nonstick spray.
In a medium nonstick skillet, melt the 2 tablespoons butter over medium heat; add celery and hot dogs. Sauté until celery is tender and hot dogs are lightly browned, about 4 minutes. Remove from the heat.
In a large bowl, dump in the cornbread mix and remove any clumps with a fork. Add in the brown sugar, dry mustard, pepper, egg, milk, sour cream, cheese, and 4 tablespoons melted butter; whisk to combine until smooth.
Set aside ¾ cup of the hot dog mixture and stir in the remaining to the cornbread mixture.
Pour batter into the prepared baking dish and spread evenly. Top with the reserved ¾ cup cooked hot dog mixture.
Bake, uncovered, for 25-30 minutes until golden brown and a tester in the center comes out clean. (Check toward the last 5 minutes of baking and tent with foil if over-browning.)
Serve portions with a nice slab of butter!
