1. Preheat the oven to 200°C.
2. Prepare the stuffing: in a frying pan, cook the breast and onion over low heat until the onion is tender and the pork is crispy.
3. Transfer to a bowl and stir in remaining stuffing ingredients. Add salt and pepper.
4. Stuff only the front of the turkey on the neck. Fold the skin under the bird and hold it in place with a skewer or by sewing it. Do not overfill as the skin may tear when cooking. Set aside the rest of the stuffing.
5. Place the onion wedges in the turkey cavity and tie the legs together.
6. Weigh the stuffed bird and calculate the cooking time: 20 minutes per 500 g and an additional 15 minutes.
7. Put the turkey in a rotisserie.
8. Baste the turkey with butter, salt and pepper.
Cover the turkey with a large sheet of foil and roast for 30 minutes. Sprinkle with the cooking juices, then lower the oven to 180°c and continue cooking for the remaining time (i.e. 3h30)
9. With your wet hands, form balls of stuffing. Set them aside.
10. Remove the aluminium for the last hour of cooking and baste turkey. 5 minutes before the end of cooking, put the balls of stuffing in the oven and bake for 20 minutes.
11. The turkey is cooked when a clear juice runs out when the fleshy part of the leg is pinched.
12. Transfer the turkey to a serving dish, cover with foil and let stand for 15 minutes before cutting.
13. For the sauce, discard the fat from the cooking juices (keep juices only). Stir in flour and cook for 2 minutes. Slowly stir in the broth and bring to the boil.
14. Adjust seasoning and pour into a gravy boat.