For the first marinade, combine all the ingredients for the marinade in a bowl. Add the chopped mutton. Cover with cling film and leave to sit in the fridge for about an hour or overnight if possible.
For the dry spice fry, heat a splash of olive oil in a very large deep saucepan.
Gradually add all the ingredients for the dry spice fry, except the chocolate, pomegranate molasses and the stock, to the olive oil.
Stir the ingredients in the oil for a few minutes until they release their aroma, then add the marinated mutton.
Allow the meat to sizzle in the saucepan (be careful, it may splatter) for a few minutes and then pour on the liquid from the marinade and the stock.
Grate the chocolate on top and add the pomegranate molasses (if using).
Cover the saucepan and leave it to cook on a very low heat for about 3-4 hours. The curry is cooked and ready to serve when the meat is soft and falls off the bone.