Prepare the Bread : Spread the bread cubes on a baking sheet and leave them out overnight to dry, or bake in a 250°F (120°C) oven for 20–30 minutes, stirring occasionally, until crisp.
Cook the Aromatics : In a spacious skillet, melt the butter over medium heat. Add the diced onions and celery, cooking until they soften, about 5–7 minutes. Blend in the minced garlic, salt, pepper, rosemary, parsley, and sage. Continue cooking for another minute, allowing the aromas to meld.
Combine Ingredients : In a large mixing bowl, combine the toasted bread cubes and cooked herb mixture. Toss gently to coat. In a separate bowl, whisk together the eggs and 2 ½ cups of stock. Pour the mixture over the bread and toss until the bread is evenly moistened. Add more stock if needed, ¼ cup at a time, until the stuffing reaches your desired consistency.
Bake the Stuffing : Preheat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish and transfer the stuffing mixture into it. Cover with foil and bake for 25 minutes. Remove the foil, drizzle with melted butter if desired, and bake uncovered for an additional 15–20 minutes, or until the top is golden brown and slightly crisp.
Serve : Let the stuffing rest for 5 minutes before serving. Garnish with additional fresh parsley if desired.