Melt HALF the butter in a large skillet. Add onions and cook over medium heat, partially covered for about 25 minutes, until tender. DO NOT BURN. Put onions in a large mixing bowl.
Melt the remaining butter in the same pan. Add apples and cook on high heat, stirring frequently until their color changes from green to yellow. Do not over cook. Add apples to the bowl.
Crumble the sausage into the same pan and cook until browned. Using a slotted spoon, remove the sausage from the pan and allow to drain on a plate covered with a paper towel. Once the grease is absorbed, add the sausage to the apples and onions.
Add the remaining 8 ingredients to the bowl. Using your hands, mix thoroughly until everything is uniformly combined. Cool the stuffing to room temperature before stuffing the turkey.
If you are cooking the stuffing in a casserole instead of the turkey, cook it at 350 degrees for 30 to 40 minutes. Baste frequently with turkey juices.