Mayo-Roasted (a month after) Thanksgiving Turkey with Gravy

Ingredients

• 5 kg whole turkey, backbone removed, neck, giblets and backbone reserved for the gravy
• 100 g coarse sea salt
• 2 sticks celery (diced)
• 1 large onion (diced)
• 1 large carrot (diced)
• 400 g good mayonnaise
• 50 g fresh parsley leaves
• 25 g sage leaves
• 10 g fresh thyme or oregano leaves
• 6 spring onions roughly chopped
• 1 lemon zested
• 1 pinch salt
• 1 pinch freshly ground black pepper
• 2 tsp neutral oil, such as vegetable, light olive oil or canola
• 2 celery sticks, roughly chopped
• 1 large onion, diced
• 1 large carrot, roughly chopped
• reserved backbone and any neck or giblets from the turkey, roughly chopped
• 500 ml chicken stock
• reserved herb stems from the Herb Mayo
• 2 bay leaves
• 50 g plain flour
• 60 g unsalted butter
• 1 tbsp soya sauce