Combine all the brine ingredients in a large pot. Bring to a boil and allow to cool completely.
Place the turkey in the brine, covering it completely and chill for 2 ½ hours.
For the Herbes de Provence paste combine the oil, butter and spice blend to create a thick paste.
Remove the turkey from the brine and pat dry. Rub with a generous amount of olive oil, coating the skin of the turkey. Then spread the paste under the skin around the breast of the turkey.
Preheat the oven to 180°C (conventional).
Strain the aromatics from the brine and place them in the bottom of a baking dish, and drizzle with olive oil. Place the turkey directly on top of the aromatics, breast side up, and place it in the oven on the lowest tray so the turkey sits in middle of the oven.
Cook for 40 minutes per 1kg for the first 4kg, then 45 minutes for every 1kg over that weight, or until the internal temperature reaches 65-70°C. For a turkey of 4.5kg weight, the cooking time should be 3½-4 hours. Baste the turkey with the tray juices every hour. If the drumsticks and wings are getting too brown, cover with foil so that they don’t burn.
To test if cooked, pierce the thickest part of the thigh with a skewer. If the juices run clear, the turkey is ready.
Transfer to a carving tray and cover loosely with foil. Set aside for 10-20 minutes to rest before carving.
