Preheat oven to 250 degrees. Butter a 13x9x2" baking dish and set aside. Scatter the ripped bread in a single layer on a rimmed baking sheet. Bake, stirring occasionally until dried out, roughly 1 hour. Let cool and transfer to a very large bowl.
Meanwhile, melt 3/4 cup butter in a large skillet over medium-high heat. Once hot add the onions and celery. Stir often until it begins to brown, roughly 10 minutes.
Add the onions and celery to the bowl with the dried out bread. Stir in the herbs, salt, and pepper, as well. Drizzle evenly 1.5 cups of broth and toss gently. Let cool.
Preheat the oven to 350 degrees.
Whisk 1.5 cups of the remaining broth with the eggs in a small bowl. Add to the bread mixture and fold in gently until thoroughly combined.
Transfer to the prepared baking dish, cover with foil, and bake until an instant read thermometer inserted to the center registers 160 degrees (40 minutes).
Remove the foil, and continue to bake until the top is browned and crisp, roughly 40-45 minutes more. Once baked, remove from the oven, and serve!