Preheat the oven to 350F. In a medium cast iron skillet over medium-high heat, crisp the bacon until the fat has rendered and the bacon bits are crispy. Add the onion and celery and cook for 3 minutes more, stirring, to soften the veggies. Turn the heat off the skillet.
In a large bowl, combine the bacon mixture, cornbread cubes, stock, melted butter, sage leaves, raw oysters, and salt. Stir gently to not break up the cornbread too much.
Press the mixture back into the cast iron skillet (see note). Bake covered for 30 minutes, then uncovered for 30 minutes until the top of the dressing is golden brown.
Serve warm. Enjoy!