Unroll the puff pastry dough, using a 2 1/2 -3 inch (6 cm) diameter circle cookie cutter, cut out circles. Remove half the circles and place on a parchment paper lined cookie sheet. The remaining disks, make a hole in the middle using a smaller cutter 1 1/2 inches (3 cm in diameter).
Prick the circles with the fork tines and brush them with the beaten egg. On each of the circles place 1-2 cut out rings, (make sure to brush the rings and edges with beaten egg. This will help keep the the vol au vent together and also gives them a golden colour).
Bake for approximately 15-20 minutes or until they appear swollen and golden. Let cool completely before filling.
SHRIMP FILLING
Cook shrimp in boiling water for about 2-3 minutes, drain well. Add to a medium bowl and toss with lemon juice, then add the mayonnaise, celery and salt and pepper to taste. Fill cooled vol au vent.
SMOKED SALMON FILLING
In a small bowl add sliced salmon toss with olive oil, salt and pepper to taste and chopped arugula. Fill vol au vent and sprinkle with parmesan flakes.
Fill the vol au vent shells just before serving or they will become soggy.