Preheat oven to 350 degrees F. Grease a 13x9 inch baking dish.
In a large skillet, heat olive oil over medium high heat. Add the bread cubes and stir to coat. Cook and stir until the bread cubes are lightly toasted and crispy, about 5-8 minutes. Set bread cubes aside in a large bowl.
In the same skillet, cook sausage over medium heat until no longer pink, stirring to break up the pieces, about 5-6 minutes. Set sausage aside in the bowl with the cubed bread. Drain most of the fat from the pan.
Add onion, celery, and garlic to the same pan. Cook and stir until vegetables are tender, about 3-4 minutes.
Add sauteed vegetables, diced apple, walnuts, dried cranberries, and fresh herbs to the bread and sausage and toss to combine. Add chicken broth, beaten egg and poultry seasoning and mix well.
Add the sausage, vegetable and bread mixture to the greased baking dish. Bake dressing, covered, for 30 minutes. Uncover and continue baking until hot and bread is slightly crispy, 15 to 25 minutes.