Salt-Baked Branzino

Preheat the oven to 190°C (375°F). In a large bowl, combine the coarse sea salt with the egg whites. Mix firmly with your hands until every grain of salt is coated and the mixture resembles wet sand — it should clump when squeezed and hold an impression of your fist. This is the mortar that will seal the fish. If it crumbles and won't hold a shape, add a fourth egg white.

Check the fish cavity is clean and dry. Season the interior lightly with a pinch of salt. Lay the lemon rounds in a shingle pattern along the cavity floor. Pack the fennel fronds, thyme, and parsley in on top of the lemon — the cavity should be visibly full. The herbs will steam inside the crust and perfume the flesh from the inside out without penetrating it externally at all.

Spread a third of the salt mixture onto a rimmed baking sheet in the exact shape and size of the fish, about 1.5 cm thick. Lay the stuffed branzino on top. Pack the remaining salt mixture firmly over the top and sides of the fish, pressing and smoothing it into a solid, even casing at least 1.5 cm thick at every point. Pay special attention to the head and tail — cracks there will let steam escape and dry the flesh. The fish should be completely invisible under the crust. Smooth the surface with wet palms.

Bake at 190°C (375°F) for 25–30 minutes for a 600g fish. The timing scales with fish weight: add 5 minutes per additional 200g. The crust will harden to a rigid, chalky shell and may develop faint ivory-to-beige colouring on top. It will not brown dramatically — the visual cues here are all about the crust hardening. A probe thermometer inserted through the crust should read 58–60°C at the thickest part of the fish. If you do not have a probe, use the timing as your guide.

Bring the baking sheet to the table. Using the back of a heavy spoon or a small mallet, crack the crust firmly along the spine of the fish. It will fracture in large shards — peel these away and discard. Carefully lift the top fillet free, then remove the spine in one piece. The bottom fillet sits on the lower salt bed — slide a spatula underneath to lift it clean. Serve the fillets on warmed plates with a generous pour of extra-virgin olive oil and the lemon slices from inside the cavity.