To make the stuffing: Place the bread, parsley, thyme and onion in a food processor. Process until you have fine breadcrumbs and the onion is finely chopped. Remove to a bowl, season and mix in the butter.
To stuff the turkey Losen the skin at the neck end with your hands. Pack the stuffing in, pushing it up between the flesh and the skin, but not too tighlty because it will expand during cooking. Tuck the neck flap under the birds back and secure with a coctail stick. Any remaining stuffing can be cooked in a covered baking dish with the turkey.
Weigh the turkey and calculate the cooking time. Allow 15-20 minutes per ½ kg. (Allow 10-15 mins per ½ kg for turkeys weighing over 8kg). Place the turkey breast side up in an oiled roasting tin. To cook the turkey.
Set the oven at Gas Mark 7, 220°C (450°F). Season the turkey with salt and pepper and dust with a little flour. Rub all over with the butter, then lay the bacon slices on the breast, overlapping each other. Cover the bacon with a piece of buttered grease proof paper. This will keep the bacon in place.
Wrap the turkey in foil and roast in the preset oven. After the first 30 minutes, reduce the heat to Gas Mark 3 (170°C or 325°F). Baste a couple of times during roasting. For the last half hour, remove the foil.
To check if the turkey is cooked, pierce the thickest part of the leg, the juices should run clear. When the turkey is cooked remove from the oven and transfer to a large plate. Reserve the cooking juices in the tin to make the gravy. Cover the turkey loosely with foil and allow to rest for half an hour in a warm place until you are ready to serve it.
Guide to good gravy: A well flavoured stock is important, so a day ahead, place the giblets, some onion slices and a bay leaf in a saucepan. Cover with water, then simmer gently for 1½ - 2 hours. Then strain and season. After removing the turkey from the roasting tin, pour off the fat and leave behind the juices.
Over a medium heat, stir in a tablespoon of flour. Blend well. Add a dash of wine. Continue to cook. Stir in the stock and simmer for 2-3 minutes. A tablespoon of redcurrent jelly, cream or balsamic vinegar will also add to the flavour. Season to taste.