Preheat your oven to 325°F (165°C). Lightly grease a 9x13-inch (23x33 cm) baking dish.
Place a large skillet over medium-high heat. Add the sausage and cook, breaking it apart with a spoon, until it is browned and cooked through. The internal temperature must reach 160°F (71°C).
Use a slotted spoon to move the cooked sausage to a very large bowl, leaving the rendered fat in the skillet.
Add the butter to the skillet and let it melt over medium heat. Add the diced celery and onion. Cook, stirring often, until the vegetables are soft, about 5 to 7 minutes.
Scrape the cooked vegetables and all the butter from the skillet into the bowl with the sausage.
Add the stuffing mix, dried cranberries, and salt to the bowl. Pour in the chicken broth and stir gently until all the ingredients are well combined and the bread is evenly moistened.
Transfer the stuffing mixture to your prepared baking dish and spread it into an even layer.
Cover the dish tightly with aluminum foil and bake for 45 minutes.
Remove the foil and continue to bake for another 15 minutes, or until the top is golden and the casserole is heated through. Let it rest for a few minutes before serving.