Cube the bread into 1-2 inch pieces then spread the bread cubes onto a large sheet pan. Loosely tent with foil and let sit overnight to get stale. Alternately, bake them in the oven at 300°F for 35-45 mins to dry them out the same day. Let them cool on the baking sheet and then transfer to a large bowl.
18-24 ounces (about 14 cups) gluten-free bread
Preheat the oven to 350°F. Spray a 9x13 inch casserole dish with non stick spray and set aside.
Melt the butter in a medium pan over medium heat. Add the onion and celery and cook for 2-3 minutes to soften. Add the garlic and all of the fresh herbs then stir well and cook for 2-3 more minutes.
1 cup unsalted butter, 2 large diced yellow onion, 5 ribs diced celery, 6 cloves garlic, 3 tablespoons fresh chopped parsley, 3 tablespoons fresh chopped sage, 2 tablespoons fresh chopped rosemary
Transfer the herb and veggies mixture to the bowl with the bread cubes and toss well.
Whisk the eggs stock, salt and pepper together in a medium bowl then pour it over the bread mixture. Stir well to combine then transfer to a 9x13 inch baking dish.
1 teaspoon kosher salt, 1/2 teaspoon fresh cracked black pepper, 2 1/2 cups chicken or vegetable broth, 2 large eggs
Bake uncovered in the pre-heated oven for 45-50 minutes. Start checking it around 40 minutes and tent it with foil if it's becoming too brown.