Preheat the oven to 450°F. Then, pulverize 1 ¼ cups of dried wild mushrooms using a coffee grinder until they form a powder.
In a mixing bowl, combine the mushroom powder with ¼ lb of room temperature cooking fat, and mix in 1 tablespoon of white wine.
Clean and dry a 10-12 lbs turkey, removing any organs from the cavity. Cut the turkey skin in several places, and use a spoon or kitchen syringe to slip the wild mushroom butter between the skin and flesh. Season the bird with garlic powder, dried thyme, poultry seasoning, salt, and black pepper. Rub the remaining mushroom butter on the turkey's surface.
Place the turkey in a large roasting pan, cover with a sheet of aluminum foil and place in the oven.
Immediately lower the oven temperature to 350°F and roast the turkey for 18 minutes per pound (about 3.5 hours for a 12 lbs turkey), basting the bird every 20 minutes.
Remove the aluminum foil 1 hour before the end of the cooking process for crispy and golden skin.
After taking the fully cooked turkey out of the oven, place it on a separate plate and cover it with a sheet of aluminum foil. Put the roasting pan on a medium heat stove top, add ½ cup of chicken stock and ½ cup of homemade sugar-free BBQ sauce, and deglaze. Bring the mixture to a boil, then remove from the heat.
Serve the sauce with the turkey immediately, and adjust the seasoning to your liking by adding more salt or pepper if needed.