Fast Way:Preheat oven to 200°. Cut bread slices into small cubes that are about 1/2-inch in size. Use serrated bread knife to cut easier. Spread bread in two large, rimmed baking sheets in one even layer and place them in the oven. Let them bake and harden for about 1-2 hours. Take them out and you can prepare the stuffing right away.
Easier Way:Cut bread slices into small cubes that are about 1/2-inch in size. Spread bread in two large, rimmed baking sheets in one even layer and set them aside on the counter to harden over 24 hours.
Prepare Sausage:
Preheat a medium cooking pan over medium heat and add half the butter.
Add diced onion and celery and cook until completely softened and add garlic. Sauté until garlic is fragrant.
(Take sausage out of the casing if needed and break it apart.) Add broken up Italian sausage to the pan and use a spatula to break up the clumps even more.
Add remaining butter and cook, stirring often and breaking up the sausage clumps, until it's completely cooked. Take off heat.
Stuffing:
Preheat oven to 375. Grease a 9x13 casserole dish. (You can also use a deep 9x9 baking dish).
In a large mixing bowl (large enough to fit everything), combine stale bread cubes, cooked sausage and veggies, herbs, salt, and pepper. Gently mix everything until evenly incorporated.
In a separate bowl, whisk the eggs and broth together and season with a little salt if needed.
Pour the liquid into the bowl with bread mixture and quickly mix everything together as evenly as possible.
Transfer into prepared baking dish and bake for 40-45 minutes.