Place bread cubes on a baking sheet and leave to dry overnight, or speed up the process by baking in a 250°F (120°C) oven for about 1 hour until dry.
Preheat your oven to a cozy 375 degrees F (190 degrees C) while you generously butter a 2 quart baking dish.
In a large skillet over medium heat, melt butter. Saute celery and onions for 10 minutes. Add mushrooms and cook for 8 minutes until tender. Season with rosemary, tarragon, chives, parsley, salt, and pepper. Mix in bread cubes and add broth until moistened. Transfer mixture to prepared dish and cover with foil.
Bake in a hot oven for 40 minutes. Uncover and bake for an additional 10 minutes until the top is crispy.