Step 1

To make the dressing, mix the oil with the lemon zest and juice, capers, mustard, some seasoning and 1 tbsp water. Don't add the parsley yet (unless serving straight away) as the acid in the lemon will fade the colour if they are left together for too long.

Step 2

Heat the oven to 220C/200C fan/gas Line a baking tray with baking parchment and put the fish, skin-side up, on top. Brush the skin with oil and sprinkle with some flaky salt. Bake for 7 mins or until the flesh flakes when tested with a knife. Arrange the fish on warm serving plates, spoon over the dressing and scatter with extra parsley leaves, if you like.