Adapted from Anne Quatrano's Summerland: Recipes for Celebrating With Southern Hospitality (Rizzoli).
Preheat oven to 350 degrees. Butter a 9-by-13-inch baking dish. Divide bread cubes between 2 rimmed baking sheets, spread in a single layer, and toast until crisp and golden, about 20 minutes. Let cool to room temperature; transfer to a large heatproof bowl.
Meanwhile, cook sausage in a large skillet over medium heat, stirring occasionally and breaking into bite-size pieces, until just cooked through, about 5 minutes.
Transfer sausage to bowl with bread. Melt butter in skillet. Add celery and onion and saute, stirring occasionally, until softened, about 5 minutes. Stir in apples and continue cooking until apples are crisp-tender, 3 to 4 minutes. Stir in sage and broth, raise heat to medium-high, and bring to a simmer. Remove from heat; immediately pour over bread and sausage. Add cranberries and stir to thoroughly combine. Season with salt and pepper.
Transfer dressing to prepared dish. Bake, uncovered, until top is crisp and golden brown, 30 to 40 minutes. Serve immediately.
The bread can be toasted up to three days ahead and stored at room temperature.