Preheat oven to 350 degrees F.
Place bread cubes in a large mixing bowl. Whisk together broth, one tablespoon of melted butter and eggs in a separate bowl. Pour over the bread cubes and mix with hands until all cubes are wet. Set aside.
Place a large cast iron skillet over medium heat and melt two tablespoons of butter in pan. Add onions and celery, cooking 5 minutes or until soft. Add garlic and cook another 2 minutes. Place sausage in pan, breaking into small pieces. Cook for about 6-8 minutes or until no longer pink.
Add apples, walnuts, sage, thyme, parsley, salt, and pepper to skillet, stirring frequently for 3-4 minutes. Stir bread mixture into sausage mixture and mix to combine. Remove skillet from heat and place in oven. Bake for 25-30 minutes or until top is golden brown. Remove from oven and let cool slightly before serving.