Preheat the oven to 350°F
Grease a baking dish
Cook and crumble any sausage, if using
Sauté onions and celery in butter until soft
In a large bowl, combine bread cubes, cooked sausage, sautéed vegetables, herbs, salt, and pepper
Whisk together broth and beaten eggs
Pour the liquid over the bread mixture
Stir until evenly moistened
Transfer the mixture to the baking dish
Cover with foil
Bake for 30 minutes
Remove the foil
Bake for 15 to 20 minutes more until golden brown
Let it rest for a few minutes before serving