In a Weber style barbecue fill the bottom with charcoal. Light the charcoal and when ready spread to cover the bottom of barbecue.
Wash the turkey and stuff with onion. Rub the exterior down with salt and pepper.
Place the turkey in a deep aluminium roasting tray. Place the pan on the barbecue's grate. Pour wine over the turkey. Cover the top of the turkey with foil.
Cover the barbecue with the lid and open the vents. Cook the turkey for 60 to 90 minutes or until meat is to your liking. Baste frequently. You might need to add water to the pan if the wine evaporates.