Preheat oven to 350°F. Arrange the bread evenly on a baking sheet. Bake until golden brown, about 8-10 minutes. Remove from oven and allow the bread to cool completely.
In a medium pan, melt 4 tablespoons of butter. Add sausage, apple, onion, and celery. Sautee until the onions are translucent. Add sugar, allspice, and sage. Continue cooking until all the ingredients are well incorporated. Remove from heat and allow to cool.
Pour 8 tablespoons of melted butter over the bread. Place the bread in a 9x13-inch baking dish. Add sausage mixture and walnuts. Toss until evenly distributed.
In a large measuring cup, combine broth, eggs, cream, salt, and black pepper. Pour mixture over bread. Allow the bread to soak the broth mixture. Stir a few times to make sure all bread is soaked.
Bake for 30-35 minutes, or until the center of the stuffing is hot, firm to the touch and golden brown. Remove from oven and let cool for 10 minutes. Serve.