1 loaf (16 ounces) day-old white bread, cut in small cubes
8 ounces bacon
4 tablespoons unsalted butter, melted
1 medium onion, diced
2 stalks celery, diced
1 teaspoon salt
1 teaspoon pepper
2 teaspoons fresh sage, chopped
1 teaspoon dried thyme leaves
1 Granny Smith apple, cored and diced
1 egg, slightly beaten
1/2 - 3/4 cup low-sodium chicken stock