To prepare the stuffing for the turkey, heat oil in a frying pan and sauté the chopped onion with the apples and mushrooms until soft and tender.
In a medium bowl, add the caramelised onion apple mushroom mixture with the bread, nuts, butter, herbs, salt and pepper. Mix well.
To stuff the turkey breast, lay the turkey skin side down. Lay the stuffing on one side of the breast (the smaller side), then tightly roll the larger side over.
Tie with cooking twine in 5-6 places, then place the turkey breast on roasting pan, and evenly brush with vegetable oil.
Roast for about one and half hours, if turkey breast is browning too quickly you can cover it with foil.
To make sure that the meat is done, using a kitchen thermometer check the centre of the chicken breast, the temperature should read 75c or 165f.
Let the turkey breast rest for about an hour, then slice and serve.
To make the sprouts with the chestnuts
Bring a large pan of salted water to the boil, then tip in the sprouts. Once back to the boil, cook for 10 minutes or until just tender then drain.
In a pan add butter with the honey and let everything melt, the mixture will become a bit syrupy at this stage. Add the sprouts with the chestnuts in the pan and cook for a minute or two. Season to taste, sprinkle with toasted pine nuts and pomegranate seeds and serve.