1. Preheat oven to 350°F (175°C) and spread sourdough cubes on a baking sheet; toast for 10–15 minutes until dry and slightly crisp, then cool.

2. In a large skillet over medium heat, cook sausage for 8–10 minutes until browned; drain excess fat and set aside.

3. Melt 1/4 cup butter in the same skillet, add onion and celery, and sauté for 5 minutes until softened.

4. Add mushrooms to the skillet and cook for 7 minutes until moisture evaporates, then stir in garlic and cook 30 seconds.

5. In a large bowl, combine toasted bread cubes, cooked sausage, sautéed vegetables, parsley, sage, and thyme; season with salt and pepper.

6. Whisk eggs and broth together, pour over bread mixture, and toss gently until evenly moistened without excess liquid.

7. Grease a 9×13-inch casserole dish with remaining butter, transfer stuffing mixture, and spread evenly.

8. Cover with foil and bake for 25 minutes, then uncover and bake an additional 20 minutes until golden brown and crisp.

9. Let rest for 5 minutes before serving.