Preheat oven to 180°.
In a small microwave-safe bowl, melt the butter (45ml), for about a minute.
Add melted butter to the bowl of the mixer, along with the crushed Oreos
and mix until fully incorporated.
Press (using your fingers) the crumb and butter mixture into a
prepared pie dish. Bake for 10 minutes, or until just set.
To the bowl of the mixer add the remaining butter, sugar, and beat
on high power until very light and fluffy, about 5 minutes.
In a medium bowl, melt the chocolate, for about a minute or 2 on
the stove, until nice a smooth.
Add vanilla, coffee, cooled chocolate, and beat on high power until
incorporated and mixture is fluffy, about 3 to 4 minutes.
Add the eggs one at a time (five minutes apart). Make sure the mixture is
smooth, silky, fluffy, with zero traces of graininess.
Turn the mixture out onto crust, smoothing the top lightly with a spatula.
Cover with plastic wrap and place in fridge for at least 4 hours
(overnight is better) for pie to set.
Add the whipped cream, smoothing it lightly with a spatula.
Sprinkle evenly with chopped chocolate before slicing and serving.