Slice the bread into cubes or tear into small pieces and arrange on a lined sheet pan. Allow the bread to sit out overnight to dry a bit or toast in the oven on a low temperature. Place the slightly dried bread cubes in a large mixing bowl and set aside until needed.
Preheat oven to 350°F (177°C).
Place a medium skillet or large pan for sautéing on the stove top and heat over medium-high, for 2 to 3 minutes until the pan is hot. Reduce cooking temperature to medium and place a stick of butter in the pan to melt.
Next, add the diced celery and onion to the pan and sauté 3 minutes. Add the diced apple and sauté for 2 minutes more.
Transfer the softened celery, onion and apple mixture with the melted butter over the bread in the mixing bowl; set aside and cook the sausage until brown breaking apart as it cooks.
Remove any excess pan drippings and transfer the cooked sausage to the bowl with the bread mixture.
Next, add the fresh chopped sage, salt, pepper, and poultry seasoning to the stuffing mixture and use a wooden spoon to gently toss and combine.
Then, slowly add the chicken stock while turning the bread mixture. The stuffing mixture should be moist but not soggy.
Grease a 13x9 baking dish with a pat of butter or with cooking spray then transfer the stuffing mixture to the prepared baking dish.
Bake 45 minutes or until the top is golden brown.
Serve the Thanksgiving stuffing with turkey or chicken and your favorite holiday sides.