After preparing a standard 1 crust pie dough recipe, blind bake the crust. In a medium, heavy saucepan, whisk until well blended the sugar, cornstarch, and salt.
Gradually whisk in whole milk.
Vigorously whisk in beaten egg yolks until they are completely blended and no yellow streaks remain.
Over medium heat, stir consistently with a whisk until the mixture thickens and starts to bubble. This should take about 8 minutes. Remove from the heat, and scrape the corners of the saucepan with a spatula.
Return to the heat, and continue to cook while stirring continuously for two minutes to completely thicken the custard.
Remove the pan from the heat and whisk in the butter, vanilla, and chopped chocolate. Stir until the butter and chocolate is melted and smooth.
Spoon the filling into the prepared crust and press a sheet of plastic wrap directly on the surface.
Let cool completely in the fridge.
Whip ¾ cup of whipping cream and spread over the top of the pie. For a sweet whipped cream, you can add 1 tablespoon of sugar to the whipped cream.
Grate chocolate over the whipped cream if desired. Use your favorite bar of chocolate. It won't take much.