Preheat oven to 375°F.
Toss the bread cubes with the melted butter, garlic, and sea salt. Spread the seasoned bread onto a sheet pan and bake for 10 minutes at 375°F, or until the tops are starting to brown.
While the croutons are baking, crumble and cook the sausage in a medium-sized pan over medium heat until it's evenly browned. Remove the sausage from the pan and set aside.
Add the celery and onion to the pan the sausage cooked in. Stir to combine and continue cooking until the celery and onion starts to wilt. Turn off the heat and set aside.
Once croutons are finished baking, reduce oven heat to 350°F. In a large mixing bowl (or the baking dish the stuffing will bake in), combine the croutons with the with cooked Italian sausage crumbles, celery, onion, rosemary, sage, and thyme.
Pour the stuffing mixture into a 9" x 13" baking dish, pour the broth over top, and bake for 30 minutes, or until the top is golden brown.
Optional: if you want to make the maple butter glaze, mix together 4 tablespoons of melted butter and 1 tablespoon of maple syrup in a small bowl 5 minutes before the stuffing comes out of the oven.
Pull the stuffing out of the oven, drizzle with the maple butter (optional), then serve and enjoy!