Mix the garlic and all the ingredients up to and including the nutmeg. Stir half of the spice mix into the yoghurt and set aside the other half. Mix the chicken with the yoghurt, cover and leave to marinate in the fridge for approx. 4 hrs.
Brown the chicken
Heat a little clarified butter in a non-stick frying pan. Brown the chicken in batches for approx. 4 mins., remove, season with salt.
Add the remaining spice mix, onions, peppers and tomato puree, pour in the water and simmer over a low heat for approx. 10 mins. Add the tomatoes, sugar and salt, bring to the boil, then simmer for approx. 5 mins. Reduce the heat, return the chicken to the pan, heat gently.
Add half of the yoghurt, mix. Scatter the coriander leaves on top and serve with the remaining yoghurt.