1.Combine the lime juice,salt and chilli powder in a large bowl. Add the chicken and mix through to thoroughly coat. Cover and set aside.
2.Heat a dry frypan over medium heat and toast the almonds,bay leaves,cloves,peppercorns,cardamom seeds and cinnamon,tossing or shaking the pan frequently,until the spices are fragrant and the almonds are starting to brown. Turn off the heat and add the ground coriander,cumin,and turmeric and toss briefly. Add the mix to a spice grinder and grind to a powder.
3.Combine half the spice powder with the yoghurt and add to the chicken. Mix through and set aside to marinate for one hour.
4.Heat the oil in a large pot over medium heat. Add the onion,garlic,ginger and the remaining spice mix and fry until golden brown.
5.Add the chicken and marinade to the pot and cook for a few minutes,stirring occasionally. Add the tomato puree,tomato paste,stock,fenugreek and chillies and cook gently for 40 to 50 minutes until the chicken is tender and the sauce has reduced by half. Adjust the seasoning and transfer to a serving dish.
6.Melt the butter in a small saucepan and cook until just turning nut brown. Pour over the chicken,garnish with coriander leaves and serve with rice and naan bread (optional).
TIPS
1.Instead of a spice grinder,you could use a clean coffee grinder,blender or stick-blender processing bowl to make the almond and spice mix.
2.Fresh spices will lose their pungency over time;buy in smaller amounts and more regularly.
3.Don't be tempted to substitute other cuts for the thighs. Chicken thighs will remain tender over a longer cooking time and contribute texture to the finished sauce.