Set the oven to 220°C/ 200°C fan/ gas mark 7/ 425°F
Grease the baking tray if you aren’t using a liner
Beat the egg for the egg wash, if using
Dry the salmon on kitchen paper. Run your fingers over the surface and ends to check for pin bones. Remove with tweezers or your fingers
Remove the skin from the salmon
Turn the salmon skin side up and run a sharp knife under the skin in the middle of a short side
Gently pull upwards and outwards as you run the knife under the skin. It should come away fairly easily - probably not all in one piece
Trim the salmon if the edges aren't square
For the Salmon en Croûte:
Chop the fresh herbs, if using. Add the herbs, salt and pepper to the cream cheese and beat well to combine
Unroll the pastry onto the baking sheet.Ignore what it says on the packet and use it straight from the fridge
Put the salmon fillet in the middle of the pastry and cover with the cream cheese mixture
Pull the sides of the pastry up to meet in the middle lengthwise and press together. You may need to stretch the pastry if your salmon is particularly wide.You probably need to wet your fingers to make it stick
Fold in the corners of the pastry and fold up the edges
If you have a lot of pastry left over, cut some off for decoration. Otherwise, you can cut any thick pieces off when it's cooked
Brush the beaten egg over the pastry. This will give the cooked pastry that golden finish