Sole Normande

Pat the sole dry with paper towels. Peel the prawns, reserving the shells, and set the prawn meat aside. Prepare all the vegetables, squeeze the lemon juice, and measure out the liquids and butter portions.

Place the prawn shells, white wine, and 200ml of the fish stock in a small saucepan over high heat. Bring to a boil, then simmer for 8 minutes until the shells are deep pink and the liquid is fragrant. Strain through a fine sieve, pressing the shells firmly, and discard shells. Reserve this prawn stock.

In a wide sauté pan over medium-high heat, combine the mussels, cider and half the minced shallots. Cover tightly and cook for 4–5 minutes, shaking the pan once, until all the mussels have opened. Discard any that remain closed. Lift the mussels out and remove them from their shells; strain the liquor through a fine sieve lined with damp muslin into a large jug — you should have about 300ml.

In a wide, shallow braising pan, melt the 30g cooking butter over medium heat. Add the remaining shallots, garlic and mushrooms and sweat for 5 minutes, stirring occasionally, until the mushrooms are softened and any liquid has evaporated.

Pour the mussel liquor, prawn stock and remaining 300ml fish stock into the braising pan and bring to a gentle simmer. Season the sole on both sides with salt and white pepper and lay them in the pan in a single layer. Spoon the liquid over the fish, cover with a cartouche of buttered parchment, and poach for 8–10 minutes until the flesh is opaque and reaches 63°C on a meat thermometer — the safe minimum internal temperature for fish.

Carefully transfer the sole to a warm serving platter using a wide fish spatula. Tent loosely with foil to keep warm. Strain the poaching liquor through a fine sieve into a medium saucepan, reserving the mushrooms separately. Bring the liquor to a rolling boil and reduce by one-third, about 8 minutes.

In a separate small saucepan, melt the remaining 30g butter over medium heat, add the flour, and stir constantly for 2 minutes to make a pale roux — it should smell faintly nutty and look like wet sand.

Ladle the reduced poaching liquor gradually into the roux, whisking continuously over medium heat, until you have a smooth, glossy veloute. Simmer gently for 5 minutes, whisking often, until the sauce coats the back of a spoon.

In a small bowl, whisk together the double cream and egg yolks until combined. Remove the veloute from the heat and slowly whisk in the cream and yolk mixture (liaison). Return to the lowest possible heat and stir for 2 minutes until the sauce thickens slightly — do not boil or the yolks will scramble.

Remove from the heat entirely. Whisk in the cold cubed butter piece by piece until each cube is fully incorporated and the sauce is glossy and rich. Add the lemon juice and adjust seasoning with salt and white pepper.

Add the reserved mussels, prawn meat and mushrooms to the sauce and stir gently over the lowest heat for 90 seconds until the seafood is just warmed through.

Spoon the sauce and seafood generously over the sole on the platter. Scatter flat-leaf parsley over the top and serve immediately.