Slick a springform pan with olive oil, then oil up around 5-6 layers of pastry, overlapping them so that all sides of the tin are covered.
Fold the filo pastry over the top and add some extra scrunched up on top for a 'lid'. - 2 or 3 pieces should be plenty. No need for an egg or milk wash as the olive oil gives a nice shine to the pastry.
The pie is also lovely cold and re-heats beautifully.