Preheat the oven at 375º F.
In a large skillet heat the butter and add the onions and the bacon strips. Add the sausage meat and the sausage. Continue cooking and separating the pork meats with a spatula.
Add the apple to the meat. Season with salt and pepper. Add the spices and mix well.
Remove from the heat and add the steamed chestnuts and cognac. Work the stuffing lightly to well incorporate the meat and chestnuts, but not mashed them.
Make 2 small incisions on each breast as well as on each thigh and insert the garlic cloves in it Add the remaining garlic in the turkey cavity. Season generously the cavity with salt and pepper.
Cover the turkey’s breast with the thick bacon slices. Cover slight with aluminum foil. Cook approximately 20 minutes per pound.
Poke with a fork once in a while to let the juices run form the breast and tight area.
Baste with white wine and any juices from the bottom of the pan every 20 to 25 minutes
When done, no more juices running out when poking the turkey, remove from the oven and let rest for 10 minutes or so covered.
Remove the stuffing before slicing the turkey and place in a serving bowl.
Slice the turkey by starting with the breast and moving to the tights. Serve alongside apple slices sautéed with butter and warm steamed chestnuts.