Luccio in Salsa alla Mantovana

Rinse the bone-in pike sections under cold water and pat dry. Heat half the olive oil in a wide, heavy braising pan over a medium flame. Lay the fish sections in a single layer and colour them lightly on both sides — the flesh should be just golden at the edges and the skin firm to the touch.

Remove the fish to a plate. In a separate pan, warm the remaining oil over a low flame and sweat the sliced onions gently until completely soft and translucent, with no colour taken — they should yield without resistance when pressed with a spoon.

Add the chopped anchovies to the onion pan and stir over a low heat until they dissolve completely into the oil, leaving no visible pieces — the smell will shift from sharp and briny to round and savoury. Add the capers and pine nuts and stir for one minute. Add the drained sultanas. This sauce is built separately so each element remains under individual control before it meets the fish.

This is where the dish lives or dies: return the fish sections to the braising pan. Pour the white wine and white wine vinegar over them in a ratio that keeps acid present but not dominant — the liquid should smell sharp but not aggressive when it meets the heat. Pour the prepared onion-and-sauce mixture over and around the fish. The vinegar cuts the mineral quality of the pike and the collagen of the bone-in sections will build the jelly that is the dish's textural key. Braise over a low flame, covered, until the fish is fully cooked through and the liquid has reduced to a saucy, slightly syrupy consistency — a skewer meets no resistance at the thickest bone-in section.

Lift the fish sections carefully into a deep serving dish — terracotta or ceramic is traditional. Pour and spoon all the braising liquid, onions, and sauce solids directly over the fish, ensuring every section is covered. Leave to cool to room temperature, then cover and refrigerate for a minimum of 24 hours — 48 hours is better. The dish is ready when the braising liquid has set to a trembling, cohesive jelly around the fish that holds its shape briefly when the dish is tilted.

Serve cold, directly from the refrigerated dish. Spoon the jellied sauce over each portion. Garnish with fresh capers and flat-leaf parsley leaves. The jelly should be fully set and the flavours — sweet, sour, salty, umami — should be completely integrated and indistinguishable in their individual origins.