Preheat oven to 300°F. Spread bread cubes on 2 large baking sheets. Bake until brown and dry, stirring frequently, 20 to 30 minutes. Let cool. Transfer to large mixing bowl.
Break up the sausage, and cook in a wide, heavy skillet until cooked through, breaking it up as you do. Remove sausage with slotted spoon and add to bread cubes in bowl. Add enough butter to the pan to make about 3 tablespoons fat altogether. Add apple and vegetables to pan. Cook until they begin to soften, 5 to 7 minutes, stirring occasionally. Stir in parsley and cook 2 to 3 more minutes. Add mixture to bread and toss gently. Blend in sage, thyme, salt and pepper to taste. Beat eggs with 3 cups water and add to bread mixture, stirring to evenly moisten the bread. Add extra broth if the dressing seems dry to you. Taste and adjust seasoning.
Butter a large baking dish (at least 9- by 13-inch). Spoon the mixture into the dish and bake at 325° for about an hour. If it seems to be getting too brown too quickly, cover with foil for second half of baking time.
Stuffing vs. dressing: I don’t recommend stuffing into the turkey, as heating requirements for the interior of the bird will overcook the meat. But cooked separately it is delicious served with turkey, chicken or pork.
Dressing additions: chopped up figs, diced fennel, prunes, nuts, cubes of roasted butternut squash or sweet potato, wild rice or just about any other grain are all great additions — if you have little amounts of leftovers of these, add them to your freezer container with the cooked onion, carrot, celery mixture. You can whip up dressing pretty darn quickly if you’ve got these already on hand.