BAKE bread ahead of time according to the loaf directions provided on the back of the Simple Mills Artisan Bread mix box and allow to cool completely. You should make 2 individual loaves of bread.
PREHEAT oven to the lowest setting.
TEAR the loaves of bread into 1-inch chunks and spread on a large baking sheet.
DEHYDRATE until completely dried out and slightly crispy, about 1-2 hours. You can also use a dehydrator or air fryer.
PREHEAT oven to 350ºF and oil a 9x13 inch baking dish.
ADD olive oil to a large skillet over medium heat and saute the onion and garlic until slightly caramelized, about 10-15 minutes.
ADD celery, leeks, sage, and thyme, and cook until softened.
POUR white wine into the mixture, and bring to a simmer. Cook for 5-10 minutes to cook off the alcohol.
SEASON with salt and pepper, adding more if needed.
MIX together the egg and bone broth in a large bowl.
ADD the dehydrated bread and apple, and pour the white wine mixture over the top, evenly distributing throughout.
TOSS well to combine, then let sit for 5 minutes to allow the bread to absorb the liquid, tossing a few more times.
SCOOP the bread mixture into the prepared baking dish and dot with butter.
BAKE the stuffing for 40-50 minutes.
SERVE immediately. Enjoy!