On a floured surface, roll out the pie crust and line a 9-inch (23cm) pie tin with it. Line the crust with parchment paper, fill with pie weights and bake for 15 minutes.

Remove the pie weights, prick the bottom and bake for another 10-15 minutes, or until the pastry is dry and lightly golden.

In a medium saucepan over medium-low heat, add the heavy cream, milk and sugar and heat until simmering.

In a medium bowl, whisk the egg yolks and cornstarch together.

One ladleful at a time, whisk in the hot cream mixture to the egg mix until it is all smooth, then return this mixture to the saucepan.

Cook over low heat for about 3 -4 minutes, whisking constantly, until the custard is thick and coats the back of a spoon.

Remove from the heat and add in the chopped chocolate, butter, vanilla extract and salt to the pot. Allow to sit for 5 minutes before whisking until smooth. (Note: Whisk VERY briefly to combine as over mixing can cause the pudding to separate)

Pass the custard through a large sieve to remove any lumps.

Pour the chocolate pudding into the prepared crust, place plastic wrap directly on the surface of the pudding and refrigerate until cold and set, at least 4 hours or overnight.

Combine the heavy whipping cream, powdered sugar and vanilla extract in a medium mixing bowl and whisk until soft peaks form.

Top the pie with the whipped cream and serve immediately. Store leftovers covered in the refrigerator for up to 2 days.