1. First, mix together the mayonnaise and lime juice and season with salt. Set aside.
2. To make the spice mix, put all the ingredients except the oil in a spice blender or mortar. Add chilli powder if you like, but this is is full of flavour and fragrance that you don’t really need it. Grind the mixture roughly, then add half the oil and mix again. Add enough of the remaining oil to make a nice paste.
3. Generously brush the salmon with the spice mix on both sides. Place the fish on the barbecue, skin-side down. Turn over after about 5 minutes and then cook for another 3-4 minutes. You want the flesh to be opaque right through. Take the salmon off the barbecue and let it rest for a couple of minutes before cutting it into portions and serving with dollops of the lime mayo.
Recipe courtesy of Waitrose