Smoked mackerel fillets, cucumber, red onion, dill, watercress, capers, and a horseradish crème fraîche dressing. The bold, smoky British coastal salad.
Slice cucumber into half-moons or use a peeler to create thin ribbons. Toss with a pinch of salt and let drain 10 minutes — the water content of cucumber is enormous.
Submerge thinly sliced red onion in cold water 10 minutes. This removes the harsh sharpness while preserving the beautiful magenta colour.
Whisk crème fraîche with horseradish cream, lemon juice, dill, and a pinch of salt. The horseradish should be assertive but not aggressive.
Arrange watercress, cucumber, and onion. Flake mackerel over in large pieces — do not break it down too fine. Scatter capers. Spoon dressing alongside.