- Preheat the oven to 200ºC/gas 6.
- Remove the heads from the mackerel, split along the belly and remove the guts. Wash thoroughly and pat dry with kitchen paper.
- Open out each fish so that it lies skin-side up and press firmly along the length to loosen the back bone. Carefully, lift the bone from the flesh then cut off at the tail end leaving the tail intact. Rinse and dry.
- In a food-processor, pulse the bread with the parsley, fresh coriander, zests, cumin, ground coriander, chilli flakes and olive oil until it forms fine crumbs.
- Arrange the mackerel flesh side up in a large baking dish and sprinkle with the breadcrumbs. Pour the stock around the mackerel but not over.
- Cook for 8-10 minutes until the fish is opaque. Meanwhile, combine all the salad ingredients.
- Serve the mackerel with any juices from the baking dish, the salad and rocket leaves.
- Mackerel fillets work just as well if you don’t like dealing with the whole fish.
- Other fish fillets such as river cobbler, cod, tilapia or trout are great with this herby crust.