Step 1

Preheat the oven to 180°C. Place a baking tray inside the oven to heat up.

Step 2

Cook peas in a pan of boiling salted water for 5-6 minutes (3 minutes if frozen). Drain and cool slightly.

Step 3

Meanwhile, combine the mint and parsley with the creme fraiche and season. Place 1 tablespoon in a food processor with the peas, lemon zest, onion and remaining herbs and pulse to roughly chop. Keep remaining creme fraiche refrigerated until ready to serve.

Step 4

Roll out 1 block of pastry on a lightly floured board to a piece slightly larger than the size of the salmon. Place on a sheet of baking paper. Pile pea mixture down the centre. Spread it out so that it is the same width as the salmon. Season the salmon, then place, best-side down, on top of the pea puree. Roll out the remaining pastry on a lightly floured board to 3-4mm thickness. Cut a long strip from the pastry the same width as the salmon and lay it on top. Brush exposed bottom piece of pastry with egg, then fold in the 4 sides and press down gently to enclose the fillet neatly (any remaining pastry can be used to decorate the croute or discard). Carefully turn the package over and, using a small knife, score the top of the pastry in a crisscross pattern, taking care not to cut all the way through. Brush with egg and transfer to the hot baking tray. Bake for 25 minutes or until the pastry is golden. Rest for 2 minutes before serving with the herbed creme fraiche.