Preheat the oven to 350°F (175°C) and grease a 9x13 inch ceramic baking dish with butter.
Place the dried sourdough cubes into a high-capacity mixing bowl.
In a large skillet, melt the butter over medium heat until foaming.
Add the diced onions and celery to the skillet; sauté for 8 to 10 minutes until the vegetables are translucent and softened.
Incorporate the minced garlic, sage, rosemary, and thyme into the skillet; cook for 60 seconds until aromatic.
Pour the butter and vegetable mixture over the sourdough cubes and toss to distribute.
In a separate vessel, whisk together the stock and the beaten eggs until homogenous.
Gradually pour the stock mixture over the bread cubes, folding gently to ensure even hydration without breaking the cubes into a paste.
Fold in the salt, pepper, and fresh parsley.
Transfer the mixture into the prepared baking dish and level the surface.
Cover the dish tightly with aluminum foil and bake for 20 minutes.
Remove the foil and continue baking for 30 to 35 minutes until the internal temperature reaches 165°F and the surface is golden brown and crisp.