Mackerel with sweet potato and lime pickle

This recipe will make more spice paste than you need, but it will keep in the fridge, with a film of oil on the surface, in a tightly covered jar for 2-3 weeks (if you keep it longer than a week, add more ginger and garlic as their flavour will diminish). It has lots of other uses add a spoonful or two to cooked rice or brush it on to chicken or lamb chops before grilling.