Summery Salmon, Cod and Prawn Fish Pie

STEP 1: MAKE THE SHORTCRUST BASE
Pulse the flour, frozen cubed butter and salt in a food processor in short bursts until the butter is in pea-sized pieces. Add the beaten egg and pulse just until the mixture starts to clump, adding ice water a teaspoon at a time only if needed. Tip out, bring together with the heel of your hand once, flatten into a disc, wrap and chill for at least 30 minutes.

STEP 2: BLIND-BAKE THE BASE (FIX-IT)
Preheat the oven to 200°C / 400°F. Roll the shortcrust to about 3 mm thick on a floured surface and line a 25 × 20 cm pie or shallow oval baking dish, pressing well into the corners and leaving a 1 cm overhang. Prick the base all over with a fork and chill for 20 minutes. Line with parchment and fill with baking beans. Bake for 15 minutes, then remove the parchment and beans and bake a further 10–12 minutes until the base is properly golden brown and dry to the touch — not pale. Cool while you make the filling. This is the single most important Fix-It correction: the base must already be cooked before the wet filling goes in.

STEP 3: MAKE THE QUICK FLAKY PASTRY LID
Coarse-grate the frozen lid butter directly into the flour and salt, tossing lightly with a knife so each shard is coated. Sprinkle over the ice water and mix with the knife only — do not knead. Bring together, pat into a rectangle, wrap and chill for 30 minutes. For visible flake, give it one fold: roll out, fold in thirds like a letter, turn 90°, roll out again and fold once more. Chill again for 20 minutes.

STEP 4: POACH THE FISH
In a wide pan, bring the milk, bay leaves, peppercorns and halved onion almost to a simmer. Add the salmon and cod and poach gently — do not boil — for 4–5 minutes, until the flesh is just opaque and barely flakes. Lift the fish out with a slotted spatula onto a plate. Strain and reserve the poaching milk. When cool enough to handle, break the salmon and cod into generous chunks. The prawns stay raw at this stage — they cook in the oven so they stay sweet and snappy.

STEP 5: BUILD THE BÉCHAMEL (FIX-IT)
Melt the butter in a saucepan and sweat the sliced leek over medium-low heat with a pinch of salt for 6–8 minutes until soft and silky but not coloured. Stir in the flour and cook for 2 minutes to a pale roux. Off the heat, whisk in the white wine, then gradually whisk in the strained poaching milk. Return to the heat and bring to a gentle simmer, whisking, until the sauce is glossy and thickly coats the back of a spoon. Now season properly: stir in the Dijon and wholegrain mustards, the lemon zest, the freshly grated nutmeg, 1 1/2 teaspoons fine sea salt and 3/4 teaspoon black pepper. Taste — it should taste slightly over-seasoned in the spoon, because the fish and prawns will mute it once folded through. Off the heat, whisk in the cream, the chopped parsley, dill and chives, and a squeeze of lemon juice.

STEP 6: COMBINE AND FILL
Gently fold the salmon and cod chunks and the raw prawns into the warm béchamel, keeping the fish as intact as possible. Taste again and adjust the salt and pepper. Spoon the filling into the part-baked shortcrust shell and level the top. Brush the rim of the shortcrust with beaten egg — this glues the lid down.

STEP 7: LID, LEAVES AND CRIMP
Roll the flaky pastry to about 4 mm thick and large enough to cover the dish with a centimetre to spare. Lay it over the filling and press the edges firmly onto the egg-washed rim. Trim the overhang flush with the dish, then crimp the edge around the entire perimeter with a fluted crimper, a fork, or by pinching with thumb and forefinger every 1.5 cm. Re-roll the trimmings and cut freehand pastry leaves, scoring veins with the back of a small knife. Arrange them on top in a generous bouquet across the centre, leaving the rest of the lid clear so the flake reads. Cut a small vent in the middle. Brush the whole lid — leaves and all — with the egg yolk wash for a deep golden finish.

STEP 8: BAKE
Set the pie on a baking sheet to catch any drips and to help the base stay hot. Bake at 200°C / 400°F for 30–35 minutes, until the lid is deeply golden and crisply flaky, the filling is bubbling visibly through the vent, and the prawns inside are cooked through. If the lid colours too quickly, tent loosely with foil for the last 10 minutes. Rest the pie for 10 minutes before serving so the sauce sets just slightly and spoons rather than runs.

STEP 9: SERVE
Bring the pie whole to the table as Miranda intended, and cut straight through the lid as Mary wanted. Serve with new potatoes dressed in butter and more dill, and a sharp green salad — a head of cos with a lemony vinaigrette is enough. A dry English white, Albariño or a lean Chablis sits very nicely alongside.