4 tablespoons olive oil
1 butternut squash cut in half, seeds removed
12 tablespoons (1 1/2 sticks) unsalted butter
1 onion, chopped
1 (16-ounce) package Sweet Italian Sausage, removed from the casings and broken into 1/2-inch pieces
4 celery stalks, chopped
1/4 cup celery leaves, chopped and reserved
8 ounces wild mushrooms, wiped clean and sliced
1 loaf challah, cut into 1-inch cubes (about 12 cups)
2 tablespoons chopped fresh sage
2 tablespoons chopped fresh marjoram
1 teaspoon sea salt
1 teaspoon dried crumbled sage
1/2 teaspoon freshly ground black pepper
1 cup low-sodium chicken broth
4 large eggs, lightly beaten