Toss the cubed butternut squash and apple with 2 tbsp of oil, and spread evenly onto the baking sheet. Bake for 45-55 minutes, or until squash is tender.
Add the remaining oil, and once warm add the onion, celery, and garlic. Sauté on medium heat.
Once the onions are translucent add the mushrooms and sausage. Cook for about 7 minutes, or until the mushrooms are soft.
Add the porcini powder, thyme, parsley, sage, salt, and cranberries. Stir well.
Remove from the heat.
Add the croutons, butternut squash, apple, and vegetable stock, and stir well to combine.
Place the cooking pot into the slow cooker, and cook on low for 30 minutes.
Cook on high for another 2 hours.
Allow the stuffing to cool and firm a bit before serving.
If you don't have a slow cooker: Keep the oven on after removing the butternut squash.
Once you've added the croutons, add 2 1/2 cups of vegetable stock. Stir well, and transfer to a baking dish. Cover tightly with aluminum foil, and bake for 45 minutes at 375°.