Place 1tsp of the lemon and dill sauce on the centre of the puff pastry square, and top with the piece of salmon fillet. Brush the pastry edges with egg glaze, then bring up the four corners to meet over the filling.
Press edges together to seal and gently knock up edges along the 'seams'. Slightly open out the centre so that the filling will be visible on cooking.
Bake for approximately 15 minutes until pastry is risen and golden. Serve with salad leaves to garnish and some of the lemon and dill sauce spooned into the top of the parcel.
N.B. Once made, store the lemon and dill sauce in the refrigerator to thicken up.