Melt butter in a large saucepan over medium heat. Add mushrooms, onions, garlic and celery and cook until tender.
Pour in chicken stock. Add parsley, sage, rosemary, poultry seasoning, salt and pepper. Let simmer for 1 minute.
Add dried bread cubes to a large bowl. Pour mushroom and herb mixture over the bread crumbs and mix to moisten the bread crumbs. They should be moist but not overly mushy. Add 1/2 - 1 cup of warm water if additional moisture is needed and mix.
Grease a 2-quart baking dish. Add the uncooked stuffing to the baking dish. Bake for 40-50 minutes or until the stuffing is slightly browned on top. Remove from oven and serve.
Storage:Tightly seal and store in the fridge for up to 3 days. Reheat in the oven or microwave.Stuffing Inside Turkey:
Do not overstuff.
Ensure the internal temperature of stuffing reaches 165F before consuming.