The original recipe yielded 12 servings, which I thought was way too much so I halved it and adjusted some of the measurements. I used chicken sausages instead of pork, but you can do as you like, or eliminate them all together for a vegetarian stuffing.
(1) 1 ½ pound loaf sliced sourdough bread with crust, cubed
Preheat oven to 325°F. Bake bread cubes on 1 large rimmed baking sheets until lightly toasted, about 20 minutes.
Sauté sausages in very large skillet over medium-high heat until cooked through, breaking into pieces with spoon, about 15 minutes. Using slotted spoon, transfer to large bowl; add bread.
Add onions and celery to same skillet and sauté until golden brown, about 10 minutes; transfer to bowl with bread. Melt 1/4 cup butter in same skillet over medium-high heat. Add apples and sauté until tender, about 8 minutes; mix apples into stuffing. Melt 1/4 cup butter in same skillet over medium-high heat. Add parsnips and sauté until golden, about 10 minutes; mix into stuffing. Melt 1/4 cup butter in same skillet. Add sage and sauté until dark green, about 2 minutes. Mix sage and butter into stuffing. Season with salt and pepper.
Butter 12x8x2-inch glass baking dish. Transfer stuffing to prepared dish; drizzle with 1/2 cup chicken broth. Cover with foil. (Can be prepared 4 hours ahead. Cover and refrigerate.)
Preheat oven to 350°F. Bake stuffing covered until heated through, about 1 hour. Uncover and bake until beginning to brown, about 10 minutes.