Masala-Marinated Chicken With Minted Yoghurt Sauce

To make the marinade, split the cardamom pods and remove the seeds. Put the cardamom seeds in a dry non-stick frying pan and discard the husks. Add the cumin and coriander seeds, cloves and black peppercorns and place the pan over a medium heat. Cook for 1-2 minutes, stirring regularly until the spices are lightly toasted - you know they're ready when you can smell the spicy aroma. Tip the toasted spices into a pestle and mortar, or an electric spice grinder, and pound to a fine powder. Transfer to a mixing bowl and stir in the fenugreek, turmeric, paprika, chilli powder, cinnamon and salt. Add the garlic, ginger and yoghurt, then mix well and leave to stand while you prepare the chicken. Place the chicken on its breast on a sturdy chopping board and cut carefully either side of the backbone with good scissors or poultry shears. Chuck out the bone and cut off the foot joints and wing tips. Strip all the skin off the bird apart from the ends of the wings (which are easier to remove after cooking). You'll find this simpler to do if you snip the membrane between the skin and the chicken flesh as you go. Cut off and discard any obvious fat - it will be a creamy white colour. Open out the chicken and place it on the board so the breast side is facing upwards. Press down heavily with the palms of your hands to break the breastbone and flatten the chicken as evenly as possible. This will help it cook more quickly. Slash the meat with a knife through the thickest parts of the legs and breasts. Place the chicken in a shallow non-metallic dish - a lasagne dish is ideal - and tuck in the legs and wings. Spoon over the marinade and really massage it into the chicken on both sides, ensuring that every bit of the bird is well coated - get your hands in there and really go for it. Cover the dish with cling film and put the chicken in the fridge to marinate for at least 4 hours or ideally overnight. Preheat the oven to 210C/Fan 190C/Gas 6 1/2. Take the chicken out of the dish and p