Ingredients

(Feeds 4-6 people)

For the chicken:
2kg (4lb 8oz) whole chicken or turkey
100g (3½oz) butter
2 whole bulbs of garlic

For the marinade:
2 medium heat green chillies, deseeded 
8 spring onions, trimmed
1 thumb of ginger, peeled
4 garlic cloves
2 tsp green peppercorns
Juice of 1 unwaxed lemon (reserve the squeezed-out halves)

For the green masala sauce:
4 tbsp olive oil
2 garlic cloves, sliced
125g (4oz) fresh spinach, washed
125g (4oz) kale, washed with hard stalks removed
Handful of mint leaves
Handful of coriander leaves (optional)
300g (10oz) full-fat Greek-style yoghurt 
Squeeze of lemon juice
½ tsp freshly grated nutmeg
Salt to taste

Instructions

Place the chicken or turkey on a trivet on a foil-lined baking tray. Put all the marinade ingredients into a blender and blitz, adding a tablespoon of water if needed to get a smooth paste. Slather this all over the bird, then cover with foil and leave to marinate overnight in the fridge.

Take the chicken or turkey out of the fridge at least 30 minutes before cooking to bring to room temperature. Preheat the oven to 200°C/180°C fan/gas 6. 

Dot the bird with the butter, then toss in the reserved lemon halves. Slice the top off each garlic bulb and add to the tray too, then cover with foil and roast for about 1½ hours (this will depend on your choice of bird and its size but as a rule allow 20 minutes per 500g/1lb 2oz, plus another 20 minutes). Uncover for the final half hour to brown the top, basting with any juices in the pan. When it’s done, remove from the oven, re-cover with the foil and then a clean tea towel and leave to rest. 

Now, prepare the sauce. Sizzle the garlic in hot oil in a saucepan over a low-medium heat, then stir through the spinach and kale. When wilted down, mix in the mint, coriander leaves (if using) and the yoghurt.

Pour in any juices from the baking tray, then transfer the whole lot to a blender and purée to a smooth sauce. Add a squeeze of lemon juice, the nutmeg and salt to taste, and serve alongside the joint with roast potatoes and vegetables of your choice.