Cut the bread into approximately 1/2-inch cubes and arrange them across a baking sheet. If the bread is already stale and dry, no additional drying is necessary.
For fresh bread, bake the cubes at 350°F for about 15 minutes, stirring them halfway through, until dry and lightly golden. Properly dried bread absorbs the broth more evenly without becoming overly soft or mushy.
Allow the toasted bread to cool slightly, then place it in a large mixing bowl.
Melt the unsalted butter in a large skillet set over medium heat. Once the butter has melted and begins to foam, add the chopped sweet onion, diced celery, and a small amount of kosher salt.
Cook for 8–10 minutes, stirring from time to time, until the vegetables are tender and translucent and the onion develops a slight caramelized color.
Stir in the freshly minced garlic and continue cooking for approximately 1 minute, just until the garlic becomes fragrant.
Add the sage, parsley, and rosemary to the skillet. If using dried sage or rosemary instead of fresh, use the specified dried quantities. Cook the herbs with the vegetables for 1 minute while stirring continuously to release their aromatic oils.
Season with freshly ground black pepper, then pour in 1 cup of the chicken or vegetable broth. Scrape the bottom of the skillet to loosen any browned, flavorful pieces and allow the mixture to simmer for another minute.
Pour the hot vegetable, herb, broth, and butter mixture over the prepared bread cubes in the large bowl.
Gently toss until the bread is evenly coated and the vegetables and herbs are distributed throughout. The warmth and moisture of the mixture should begin softening the bread without completely saturating it.
In a separate bowl, whisk the remaining 1 1/2 cups of chicken or vegetable broth together with the 2 room-temperature eggs until completely blended.
The egg-and-broth mixture provides the moisture and structure needed to produce stuffing that remains cohesive rather than dry and crumbly.
Transfer the stuffing to a buttered baking dish and spread it into an even layer.
Bake at 350°F for 45–50 minutes, or until the surface is golden brown and a knife inserted into the center comes out clean.
If the surface begins browning too rapidly, cover the dish with foil for approximately the first 30 minutes of baking. Remove the foil for the final 15–20 minutes so the top can develop a crisp, golden finish.
Remove the herb stuffing from the oven and allow it to rest for 10 minutes. This brief resting period helps the interior set and makes the stuffing easier to portion.
Immediately before serving, scatter fresh sage, parsley, rosemary, or a combination of the herbs over the top for additional color and fresh herbal flavor.