Process Arnott’s Tim Tam in a food processor to a fine crumb. Combine Tim Tam crumb with butter, press into the base and sides of a greased 23cm loose bottom flan tin. Bake for 15 minutes and cool, leaving in flan tin.
Meanwhile, make the chocolate custard by whisking together eggs, vanilla, sugar, cocoa, corn flour and salt in a medium sized saucepan. Gradually whisk in milk until smooth. Place saucepan over high heat, bring to the boil, stirring continuously. Remove from heat, add chocolate and whisky, and stir for 1 minute or until chocolate is melted and custard is smooth. Transfer to a bowl, cover with plastic wrap, set aside for 1 hour to cool to room temperature.
Once the custard has cooled, spoon the custard into the pie shell and refrigerate for 4 hours or until set. To make the vanilla cream, whisk cream, vanilla and icing sugar together until soft peaks form. Spoon cream over the top of the pie, garnish with chocolate shavings.