Preheat oven to 190°C.
Strech out the rashers.
Put the turkey into a roasting dish, then rub it with some butter or margarin. Season with pepper.
Lay a few sage leaves on top of the bird.
Put the bacon rashers on top of the bacon, horizontally and diagonally, creating a criss-cross pattern. Tuck the loose ends underneath the crown.
Pour the stock into the roasting dish, add the onion, then cover the turkey with foil.
Roast for about 2 hours ( 1hr 10min plus 20 min/kg).
Mix the mustard and maple syrup.
Remove the foil for the last 20 minutes of roasting. Using a silicon brush, glaze the bacon with the maple-mustard mixture. Return the dish to the oven, uncovered, for the remaining cooking time. Check the turkey. Pierce the thickest part of the meat with a skewer - if the juices run clear it’s cooked through properly. If it’s still pink, roast for another 10 minutes and check again.
When the turkey is done, transfer it to a plate, cover with foil and kitchen towel and let it rest for 30min.
Serve with roasted vegetables.