Put a dry frying pan over a medium heat and add coriander, fennel and cumin seeds, and cloves. Toast, shaking the pan every now and then, for a minute or two. Tip into a pestle and mortar and crush to a rough powder, add cinnamon and stir to combine. Put the goat meat in a bowl and coat with the rub. Cover with cling film and refrigerate until needed (ideally leave it overnight, but 30 minutes is better than nothing.) Heat a little oil in a saucepan and fry the onions for a couple of minutes until soft. Add garlic, chillies and Nigella seeds and stir for another minute before turning up the heat and adding the goat. Stir over a medium-high heat for a few minutes until the meat starts to colour.