River Cottage merguez mackerel fillets

Method

1. Place the fennel, cumin and coriander seeds and the peppercorns in a dry pan and toast over a medium heat for a few minutes, shaking often, until fragrant. Put in a pestle and mortar, add the cinnamon and grind to a coarse powder. Add the salt, garlic, oil, lemon zest, paprika and cayenne (the faint-hearted can leave out the cayenne). Grind to a paste.
2. Gently coat the flesh-side of the mackerel fillets with some of the paste. Try not to get any on the skin-side if you can help it (a little may be unavoidable).
3. Place the fillets, skin-side up, in a dish, cover and refrigerate for at least an hour. This allows the flavours to penetrate and will also slightly cure the flesh, making it firmer and easier to barbecue.
4. Drizzle the mackerel skin with a little oil and, while the barbecue is still good and hot, place the fillets skin-side down on the grill. Cook until the skin is crisp and slightly charred, then, using a carving fork or fish slice, lift the fillets and turn them to cook on the flesh side for a minute or two. Remove from the grill and place on a serving dish. Squeeze over a little lemon juice, sprinkle with chopped coriander or cress, then serve.