Salt Cod Liver Lyonnaise

Drain the salt cod livers thoroughly and pat completely dry with kitchen paper. Slice any very large lobes into roughly 3 cm pieces. Measure out the vinegars, sugar, thyme, garlic and parsley so everything is at hand before cooking begins.

Place a wide, heavy-based skillet or cast-iron pan over medium-low heat and add the duck fat. Once shimmering, add all the sliced onions and a generous pinch of salt. Stir to coat, then spread into an even layer.

Cook the onions, stirring every 4–5 minutes, for 35–40 minutes until deeply golden, jammy and reduced to roughly a quarter of their original volume — they should smell sweet with no raw sharpness remaining.

Add the garlic and thyme leaves to the caramelised onions and stir for 2 minutes until fragrant, keeping the heat at medium-low.

Add the sugar, red wine vinegar and sherry vinegar to the pan, scraping up any fond. Cook for 3–4 minutes until the vinegar has reduced by half and the onions are glossy and lightly syrupy. Slide the onion mixture to one side of the pan.

Raise the heat to medium-high and add the butter to the cleared side of the pan. Once foaming, lay the cod livers in a single layer and sear without moving for 2–3 minutes until a golden crust forms on the underside.

Gently turn the livers and cook for a further 2 minutes until just cooked through — they should be firm but still yielding at the centre. Use a probe thermometer to confirm an internal temperature of 63°C.

Fold the caramelised onions back over and around the livers, reduce the heat to low, and allow the flavours to meld together for 1 minute. Scatter over the chopped parsley and season with fleur de sel and black pepper.

Toast the bread slices under a grill or in a dry pan until crisp and golden. Spoon the livers and onions over the toast and serve immediately.