Preheat the oven to 350°F. Grease a 9x13-inch casserole dish.

In a large pan, add sausage and cook over medium heat until no longer pink; breaking it into small pieces as it cooks. Drain sausage on paper towels. Set aside.

In a large saucepan over medium heat, melt 1 stick of butter. Add celery and onion, then sauté in the butter until vegetables soften (about 1-2 minutes).

Add chicken broth and the other two sticks of butter. Heat until butter is completely melted, stirring frequently (if the mixture starts to foam up while butter is melting, lower the heat).

Remove from heat and add in rubbed sage seasoning, salt, and pepper; mix well. Pour in both packages of stuffing mix and stir until fully moistened. Add in the cooked sausage and mix until well combined.

Pour the mixture into the greased casserole dish and spread evenly. Cover with tin foil. Bake covered for 30 minutes. Take out of the oven and stir stuffing to make sure it’s not too moist on the bottom of the dish. Return to the oven and bake uncovered for an additional 15 minutes or until the top is a bit crispy, then serve hot!