- Nonstick vegetable oil spray
- 4 cups 1/2- to 3/4-inch cubes peeled, seeded butternut squash (from one 1 3/4-pound squash)
- 1/2 cup (1 stick) unsalted butter
- 3 cups chopped onions (about 1 pound)
- 2 cups chopped celery (4 to 5 stalks)
- 1 1/2 cups coarsely chopped fresh fennel bulb (about 1 medium)
- 1 1-pound pork sausage log
- 1/4 cup chopped fresh Italian parsley
- 2 tablespoons chopped fresh sage
- 2 tablespoons chopped fresh marjoram
- 12 cups (generous) 1-inch cubes day-old pain rustique or ciabatta bread with crust (about 1 1/4 pounds)
- 1 1/2 teaspoons fine sea salt
- 1 teaspoon coarsely ground black pepper
- 1 cup (or more) low-salt chicken broth
Preheat oven to 350°. Spray rimmed baking sheet with nonstick spray. Scatter squash on sheet in single layer; sprinkle lightly with salt and pepper. Roast squash until tender, stirring occasionally, about 55 minutes. Transfer to large bowl; cool.
Melt butter in heavy large skillet over medium heat. Add onions, celery, and fennel. Sauté 8 minutes. Add sausage. Sauté until vegetables are tender and sausage is cooked through, breaking up sausage with fork, about 10 minutes. Add all herbs; sauté 1 minute longer. Add to bowl with squash. DO AHEAD: Can be made 1 day ahead. Cool, cover, and chill.
Preheat oven to 350°. Divide bread between 2 rimmed baking sheets. Bake until bread is crusty but not hard, reversing sheets after 5 minutes, 10–12 minutes total. Transfer to very large bowl and cool.
Butter 13x9x2-inch baking dish. Stir vegetable mixture into bread. Whisk eggs, salt, and pepper in small bowl to blend well; whisk in 1 cup broth. Add egg mixture to stuffing, tossing to combine evenly and adding more broth by 1/4 cupfuls if dry. Transfer stuffing to prepared dish.
Bake stuffing uncovered until cooked through and brown and crusty on top, 50–60 minutes. Let stand 10 minutes.