Challah, Wild Mushroom & Herb Stuffing

Ingredients

• 1 large loaf challah ((about 1 pound))
• ½ cup (1 stick) unsalted butter, (plus more for buttering baking dish)
• 2 cups yellow onion, (diced, from 2 medium onions)
• 2 cups celery, (diced)
• 2 cups wild mushrooms, (diced)
• 2 tablespoons finely chopped fresh thyme ((or 1 teaspoon dried))
• 1 tablespoon finely chopped fresh rosemary ((or ¼ teaspoon dried and crumbled))
• ½ teaspoon finely chopped fresh sage ((or ¼ teaspoon dried))
• 1½ teaspoons salt
• 1 teaspoon freshly ground black pepper
• 3 cups chicken broth