Grease a 15-cm pie foil tin. Unroll the pastry onto a lightly floured surface and roll out lightly.
Cut out a circle slightly bigger the tin. Place the pastry into the tin and prick the base with a fork.
Cook for for 15-20 minutes in the air fryer, until the pastry is light golden in colour. Remove from the air fryer and cool.
Heat the milk over low heat with the chai tea bags.
Bring the milk to a boil, then reduce the heat and remove the tea bags. add the sugar, flour, cornflour and a pinch of salt, whisking well to prevent lumps.
Cook, stirring, until thickened, then add the butter.
Whisk in the eggs and vanilla.
Pour the filling into the pie crust and cook for 25-30 minutes, until the filling is set. To prevent the filling from browning too much, place a sheet of baking paper over the top halfway through cooking.