Preheat oven to 160°C fan forced.
Using a medium-large saucepan, cover pumpkin pieces with water and bring to a boil, place a lid on top and simmer for 15 – 20 minutes. Drain and let cool.
Roll out filo pastry sheets. Using a 25cm pie dish with a removable base, gently layer the filo sheets one by one, draping the extra pastry over the edge. When the dish is evenly lined, use a fork and prick all over the base. To finish, carefully take the overlapping filo pastry and shape around the rim. Brush all over with melted butter and bake in the oven for 15 – 20 minutes until light golden brown. Remove and leave to cool completely (if the pastry on the base has risen, carefully press it down to flatten).
To make the filling: Push cooled pumpkin pieces through a sieve to make a puree. Combine beaten eggs, sugar, salt, cardamom, 25gm melted butter, milk and cream, then add the pumpkin purée and stir to combine.
Pour evenly into the filo pie shell and bake for 30 minutes or until the filling is set.
Leave to cool before removing the pie from the tin and serving.