1. Lay out the fillets on a flat tray and squeeze lemon juice on them. Season well with pepper and scrape lemon zest over the fillets. Just before cooking sprinkle a little olive oil over the fish.
2. Place the tray on a pre-heated BBQ and close the lid. The fillets will take about 5 minutes to cook. Cooking on the BBQ adds a great smokey flavour to the fish. If you do not have a BBQ then it works just as well under the grill.
3. Serve with your favourite salad and a spoonful of horseradish which works really well with Mackerel.
What could be simpler than that?