Toast cardamom seeds, cumin, coriander, cloves, and peppercorns in a dry pan for 2 minutes.
Grind toasted spices into a powder and mix with fenugreek, turmeric, paprika, chilli, cinnamon, salt, garlic, ginger, and yoghurt.
Spatchcock the chicken by cutting along both sides of the backbone and removing it.
Remove the skin and visible fat from the chicken bird.
Flatten the chicken by breaking the breastbone and slash the thickest parts of the meat.
Coat the chicken thoroughly with the marinade and refrigerate for 4 hours or overnight.
Preheat the oven to 200°C and place the chicken on a rack in a roasting tray.
Roast for 60 to 75 minutes, adding lime quarters for the final 20 minutes.
Rest the meat for 10 minutes, then serve with a sauce made of yoghurt and mint.