Prepare turkey: Remove from the fridge and unwrap one-two hours before roasting. Remove the giblets if they are inside the turkey. Carefully pat the skin dry with kitchen paper.
Preheat oven: Start preheating the oven to 220 degrees Celsius/ 430 degrees Fahrenheit about ½ hour before the turkey needs to go in the oven.
Season: Melt the butter in a small pan. Use 1 tablespoon of it to smear the turkey inside the cavity. Rub it inside with 1 teaspoon fine sea salt and some pepper as well.
Stuff: Quarter one onion and one orange. Place the wedges and the rosemary inside the body.
Bind the legs with kitchen twine.
Assemble: Place the remaining halved or quartered onion and orange in the roasting tin. Place a rack on top (See note 5 for substituting a rack). Place the turkey, breast side down, on the rack. Brush with half of the melted butter. Pour the red wine in the tin, around the turkey, not on it.
Roast at high temperature for 30 minutes.
Flip: Remove from the oven and turn the heat down to 170 degrees Celsius/ 340 degrees Fahrenheit. Turn the turkey breast side up and brush well with the remaining melted butter (if the butter is not melted anymore, reheat).Pour the water into the tin around the turkey.
Roast at a lower temperature for one hour. Check from time to time, if the skin turns too brown too soon, cover it loosely with aluminum foil (it depends on your oven). Check 10 minutes before the roasting time is over. If the skin is not brown enough, increase the temperature to 220 degrees Celsius/ 430 degrees Fahrenheit again.
Check the internal temperature with a kitchen thermometer: it should be 75 degrees Celsius/ 165 degrees Fahrenheit (Note 6). If the turkey is not quite there yet, roast for 5-10 more minutes and check again.
Rest: Remove from the oven and transfer to a large plate, cover loosely with aluminum foil and let rest for 30 minutes.In the meantime, make the red wine gravy.