Preheat oven to 180°C / 350°F / gas Mark 4, 10 minutes before cooking. Remove the giblets and neck from inside the turkey if applicable, and wipe the turkey inside and out with a clean damp cloth. Season the body cavity, then place the onion wedges, lemon and bay leaves in the body cavity. Cover while making the stuffing.
Heat the oil in a pan and gently sauté the onion, garlic, carrot and celery for 5 minutes or until softened. Remove from the heat and stir in the shredded spinach, pine kernels, egg, lemon rind and juice with the breadcrumbs and seasoning to taste. Mix to form a stiff consistency.
Stuff the neck cavity only with the prepared stuffing, then fold over the neck flap and secure by either sewing using fine twine and a trussing needle or with skewers. Roll the remaining stuffing into small balls and cook round the turkey for the last 20 minutes of the turkey cooking time.
Weigh the turkey and calculate the cooking time allowing 20 minutes per kg + 90 minutes at the end. Place the breast side down in the roasting tin and place in the preheated oven. (Cooking the turkey breast side down allows the juices from the turkey to naturally baste the turkey during cooking.) Twenty minutes before the end of the cooking time, turn the turkey the right way up and place the stuffing balls round the turkey to cook. (If you find the turkey is browning too quickly, cover lightly with tin foil) Check the turkey is thoroughly cooked by inserting a long skewer in the thickest part of the thigh. If after 1 minute the juices run clear, the turkey is cooked.
Remove from the oven, place on the serving platter, cover lightly with a clean cloth or tin foil and leave for about 15-20 before carving. Use juices to make gravy. Garnish with the filo baskets, stuffing balls, lemon wedges, zested lemon rind and flat leaf parsley
Make the filo baskets by cutting the pastry into 10cm / 4inch squares. Lightly brush a square with water and place a second square on top. Repeat making 4 layers in total. Place in a deep muffin tin taking care not to tear the pastry. Crumble a small piece of tin foil and place in the centre. Repeat until the pastry has been used. Bake in a preheated 200°C / 400°F / Gas mark 6 for 10 minutes or until golden. Remove the tin foil and store in an airtight tin. If necessary, crisp in a hot oven for a few minutes before using. (If no muffin tins are available use inverted dariole moulds or ramekins to shape the baskets)
For the stuffing:
For the filo pastry