Preheat the oven to 375°F. Slice your sourdough boule into thick slices. Rip or cut the slices into small pieces.
Chop up celery, carrots, and onions. Saute the vegetables on low heat with a tablespoon of butter and a teaspoon of sea salt.
Cut up the squash into small cubes and add that to the sauteed vegetables.
Chop the herbs up finely and set aside.
Toss the bread with the sauteed vegetables, squash, and fresh herbs, reserving a handful of herbs to sprinkle on top for presentation.
Pour the chicken stock and eggs over the bread mixture and lightly toss to combine, trying not to break the bread.
This part is optional, but I do like to drizzle the top of the stuffing with 2 tablespoons of melted better to crisp up the top a bit and add more richness to the dish.
Once the oven reaches 375°F, cover the stuffing with a sheet of foil and bake for 20 minutes. Then uncover the stuffing and bake for an additional 10 minutes. For a crisp top, don't cover the stuffing at all.
When the stuffing is cooked through, it should be soft, but not soggy, with a browned top. Sprinkle the reserved herbs on top and serve immediately.