Salt & Vinegar Line Caught Blue Mackerel Recipe

Prepare brine

In a non-reactive bowl or container large enough to hold the fish, combine cold water, coarse sea salt, white vinegar, sugar, black peppercorns and bay leaves. Stir until salt is dissolved. Chill the brine until cool (about 10 minutes).

Brine the mackerel

Rinse the cleaned mackerel under cold water and pat dry with paper towels. Submerge the whole mackerel in the chilled brine so fish are fully covered (use a plate to weigh them down if necessary). Refrigerate for 20–30 minutes for a light salt-and-vinegar cure. Do not over-brine — 20–30 minutes gives a bright salty-vinegary note while keeping texture tender. Remove fish from brine and rinse lightly under cold water, then pat dry thoroughly. Let sit on a rack for 10 minutes to air-dry slightly; this helps form a good sear.

Portion and score

If preferred, fillet the mackerel into two fillets per fish (skin on) or leave whole. Lightly score the skin with 2–3 shallow diagonal cuts per side to prevent curling during searing. Season the skin side very lightly with a pinch of extra salt (the brine already seasoned the flesh).

While the fish rests after brining, prepare the Gordal olive brine dressing. Roughly chop the Gordal olives and transfer to a small bowl. Add the Gordal olive brine, extra-virgin olive oil, lemon juice, lemon zest, chopped parsley and freshly ground black pepper. Whisk briefly to emulsify into a loose vinaigrette. Taste and adjust acidity with a little more brine or lemon if needed. Keep chilled until serving.

Bring the softened cultured butter to room temperature if not already soft. Generously spread butter on one side of each sourdough slice.

Heat a large heavy skillet or griddle over medium heat. Add a small amount of neutral oil to the pan and sear the buttered side of the sourdough slices butter-side-down until golden brown and crisp, 2–3 minutes. Flip and toast the other side briefly (30–60 seconds) so bread is warm throughout. Remove and keep warm. Sprinkle toasted slices lightly with flaky sea salt and a grind of black pepper.

Heat a large non-stick or well-seasoned cast-iron skillet over medium-high heat until hot. Add the neutral oil and swirl to coat. Place the mackerel skin-side down in the pan. Press gently with a spatula for the first 20 seconds to ensure even contact between skin and pan.

Sear skin-side down without moving for 2–3 minutes, or until the skin is deeply golden and crisp. Flip and cook the flesh side for 30–60 seconds more for fillets (a little longer for whole fish depending on thickness) until just cooked through but still moist (internal temperature ~52–56°C / 125–133°F for medium). Remove to a cutting board and rest for 2 minutes.

If serving whole fish, transfer to serving plates. If filleted, portion into serving pieces (2 fillets per fish or as desired).

Arrange 1–2 slices of toasted Fiore sourdough on each plate. Lay the seared mackerel pieces atop or alongside the bread. Spoon 1–2 tablespoons of the Gordal olive brine dressing over the fish and a little onto the bread. Scatter chopped Gordal olive pieces (from the dressing) over the fish, then sprinkle microgreens or baby parsley around for freshness.

Finish each plate with a small pinch of flaky sea salt over the fish, a few turns of freshly ground black pepper, and a lemon wedge on the side for extra brightness.

Serve immediately while the bread is warm and the fish skin is crisp.