Preheat the oven to 400˚F. Place the bread cubes in a 9 x 12 inch baking dish. Bake for 20 minutes, tossing halfway through. Remove from the oven and set aside.
Meanwhile, heat butter and olive oil in a large skillet over medium heat. Once melted and shimmering, add the mushrooms and cook for 10 minutes until the moisture has evaporated.
Add the onions and celery, cooking for another 5-6 minutes until they begin to soften. Add garlic, sage, thyme, rosemary, soy sauce, salt, and pepper, and continue cooking another 1-2 minutes until the garlic is fragrant. Add the broth to deglaze the pan and remove from heat.
Transfer the mushroom mixture on top of the toasted bread cubes along with the parsley,and gently toss until well combined and the liquid is absorbed.
Bake for 30 minutes or until the top is browned well.
Notes
Storage: Kept in a fridge in an airtight container, this stuffing will last for about 4 days. To reheat it, pop it in a 350˚F oven until warmed through. If you're worried about it drying out, you can cover it with foil.