Tuna Steaks with Crunchy Cucumber Relish

Light the barbecue, and allow the flames to die down until the charcoal is ready to cook on (this will take about 30 minutes – for more info, see our handy guide, Getting the Most from a Charcoal Barbecue). Brush the fish steaks generously all over with oil, and season well with salt and pepper.

While you wait for the barbecue, make the relish. Cut the cucumber in half lengthways and use a teaspoon to scoop out (and discard) the seeds. Chop the cucumber into small dice and put them into a mixing bowl, then cut the onion into small dice and add them to the bowl, too. Measure in the vinegar, then add a generous pinch of salt, plus the honey and mustard seeds, and give everything a good scrunch together with your hands. Next, finely chop the celery leaves (if using) and parsley, and add them to the bowl, together with the oil and a few turns of the pepper mill. Stir well, check the seasoning is OK, and set aside until needed.

When the barbecue is ready, place the fish steaks on the grill and cook for 2-3 minutes on each side, or until cooked through. Serve straight away, with the relish alongside.