Preheat oven to 350 F, and oil a large casserole dish.
In a large pan, heat oil over medium heat. Add mushrooms, paprika, garlic powder, fennel seeds, and black pepper, and saute until all liquid is absorbed and mushrooms are starting to stick to the pan; about 10 minutes.
Add onion, celery, and apples to the pan. Cook for a few minutes and turn off heat.
Pour bread cubes into a large bowl or stock pot. Add mushroom mixture, and the rest of the ingredients. Mix well. Start with one cup of broth. Add a little more if the stuffing seems dry, being careful that it doesn’t get soggy. Transfer to greased casserole dish.
Bake, covered, for 30 minutes. Remove cover, and bake uncovered for 15 minutes.
Garnish with chopped parsley or sage leaves if desired.