Salmon en croute

For the béarnaise sauce

1. Put the shallots and the tarragon vinegar into a small saucepan and warm gently.
2. Add the egg yolks and a splash of cold water to a liquidiser. Add in the shallot and vinegar mixture and pulse. Slowly trickle the hot butter into the mixture and keep blitzing until it has all been added and the sauce has emulsified. Add in the herbs and blitz again.

For the salmon en croûte

1. Pre-heat oven to 220°C/gas mark 7. Line a baking sheet with parchment paper.
2. Roll the pastry on floured surface to 1/8 inch thickness and cut in half. Place half the spinach on each piece of pastry lengthwise and top with the salmon. Season, add a spoonful béarnaise sauce then top with remaining baby spinach.
3. Brush one side pastry with egg solution. Fold in half, folding in the sides to seal completely. Crimp the pastry and score the top. Brush with egg. Bake for 15 to 20 minutes or until golden and risen.