Take both pieces of pastry out of the fridge & leave to sit at room temperature for 20-30 minutes, depending on how hot your kitchen is.
Next, place one piece of pastry onto a lightly floured worksurface then using a rolling pin, beat the top of the pastry all over (this makes it more pliable).
Dust the pastry lightly with flour then roll out into a circle that is slightly larger than your pie tin. Make sure to turn the pastry 45° after every roll & to lightly dust the pastry with flour as is needed. The pastry should be around 3mm thick.
Carefully roll pastry around your rolling pin then unroll into a 9" pie tin that has been lightly greased with butter. Gently press the pastry into the tin. The pastry should be overhanging the edge by a couple of centimetres.
Fill the pie crust with your chosen pie filling.
Roll out the remaining piece of pastry into a 3mm thick circle, the same way as before.
Brush the edge of the pie lightly with cold water then lay the pastry circle on top of the pie, pressing the edges lightly, to seal. Thin the pastry out slightly between your fingers then trim the edges with a pair of scissors, leaving around 1cm overhanging.
Fold the overhanging edge back onto the rim of the pie dish & crimp as desired.
Cut a cross in the middle of the pie (to let the steam out as it bakes) then chill in the fridge for at least an hour.
Bake & egg wash according to your chosen recipe's instructions.With my pie recipes, I tend to bake at 200°c/180°c fan (392°f/356°f) for 40-45 minutes, until a deep golden brown.