Gurnard Chowder

STEP 1: PURGE THE SHELLFISH

Cockles and razor clams both hold sand, and grit in the finished sauce is the one failure that cannot be repaired later. Cover them in cold water salted to roughly the salinity of seawater (about 35 g of salt per litre, or 2 tablespoons per quart) and leave for an hour in a cool place, changing the water once. Scrub the mussels and pull the beards. Discard any shell that is cracked, or that stays open when tapped sharply. Rinse everything in fresh cold water before cooking.

STEP 2: OPEN THE SHELLFISH AND BUILD THE STOCK

This stock is the foundation of the sauce, and the point of Patrick's method is that the shellfish do double duty. Melt the butter in a wide lidded pan over medium heat and sweat the shallots, garlic, thyme and bay leaf for 3-4 minutes without colour. Raise the heat, pour in the white wine and bring to a hard boil. Add the mussels and cockles, clamp the lid on and cook for 3-4 minutes, shaking the pan once, until the shells open. Lift them out with a slotted spoon. Add the razor clams to the same liquor and cover for 60-90 seconds only - they need barely any time and turn to elastic if pushed. Remove them at once. Discard any shell that stayed shut. Strain the cooking liquor through a fine sieve lined with muslin or a coffee filter and let it settle; pour off the clear stock and leave the last grainy spoonful behind. You want about 2 cups (480 ml); if you are short, top up with water rather than boiling it down, which will over-salt it.

STEP 3: PICK AND HOLD THE SHELLFISH

Pick the mussel and cockle meats from their shells, keeping a few of the best mussels whole for the garnish on top of the leek disc. Slide the razor clams from their shells, cut away the dark digestive sac and the tough tip, and slice the white meat into 1 cm pieces. Keep all three separate, covered, at cool room temperature - not in the fridge, which firms them, and not in liquid, which leaches them. They will be warmed through in the sauce at the last moment, never cooked again.

STEP 4: MAKE THE CHOWDER SAUCE

Melt the butter in a heavy saucepan over low-medium heat. Sweat the diced leek and celery with a pinch of salt for 6-8 minutes until soft and sweet with no colour at all - colour here turns the sauce grey and dulls the shellfish. Stir in the grated ginger and cook for one minute more, until fragrant. Add the diced potato, the vermouth and the clarified shellfish stock. Simmer gently for 12-15 minutes until the potato is completely soft. Blend until smooth, then pass through a fine sieve back into the clean pan, pushing hard with a ladle. Stir in the cream and return to a bare simmer for 3-4 minutes to thicken to a pouring consistency that just coats the back of a spoon. Take it off the heat, add lemon juice a few drops at a time, and taste as you go - the acidity is what stops a cream-and-shellfish sauce turning cloying, and it should lift rather than announce itself. Season with salt only now, at the very end. Keep warm below a simmer; boiling after the cream goes in will split it.

STEP 5: COOK THE GURNARD

Gurnard is armoured and bony, so if you are filleting it yourself take real care to scale it thoroughly, skin it cleanly and run your fingertips along the fillet to find every pin bone. Salt the fillets lightly on both sides and leave for 10 minutes, then pat dry. Seal each fillet in a vacuum pouch with a knob of butter and a little lemon zest, laid flat without folding. Cook at 56C (133F) for 12 minutes - Patrick's exact setting. The fish will be opaque and set but will still flake into clean, translucent leaves. Do not go higher or longer; gurnard is lean and turns cottony fast. Without a circulator: butter a shallow dish, lay the seasoned fillets in it, add 2 tablespoons of the shellfish stock, cover tightly with foil and bake at 250F (120C) for 10-12 minutes, until the centre reads 122F (50C).

STEP 6: MAKE THE LEEK DISC

Trim the leeks to lengths and cut each lengthways down one side so the layers separate into flat sheets. Blanch the sheets in boiling salted water for 60 seconds, then plunge into iced water and pat completely dry. Melt the butter in a wide pan, lay the leek sheets flat and add the vegetable stock; braise gently, covered, for 5-6 minutes until tender. Use vegetable stock here rather than the shellfish stock, which is needed in full for the sauce. Cool slightly, then stack the sheets flat, layer on layer, and press between two sheets of parchment under a light weight for 20 minutes. Cut discs with the ring cutter - one per plate, sized to sit on top of the fish. Warm through gently before serving.

STEP 7: TRIM AND PLATE

The geometry is part of this dish, not decoration. Open the pouches and lift the fillets onto kitchen paper and rest them for a minute. Using the ring cutter, trim each fillet into a clean disc - keep the trimmings, they are excellent stirred into the sauce. Set a gurnard disc slightly off centre in a warm shallow bowl. Lay the leek disc squarely on top and garnish it with the reserved whole mussels. Arrange the cockles and sliced razor clam around the base. Add the picked chives and dill. Warm the remaining shellfish meats through in the chowder sauce for 30 seconds off the heat, then finish the sauce with a thread of olive oil and, if you like, a brief blitz with an immersion blender for a light foam at the surface. Pour the sauce into a warm jug.

STEP 8: SERVE

Bring the bowls and the jug to the table together and pour the chowder around the fish in front of your guests. Patrick served the sauce separately and poured at the pass; keeping it off the plate until the last second is what protects the leek disc and the surface of the fish. Serve immediately, with good bread.