For the crust, combine the graham cracker crumbs, sugar and butter in a bowl. Press the mixture into an 11-inch false-bottom tart pan, making sure the sides and the bottom of the crust are an even thickness. Bake for 10 minutes and set aside to cool completely.
In the bowl of an electric mixer fitted with the paddle attachment, combine the sugar, egg yolks, cornstarch and salt. With the mixer on low, slowly add the scalded milk until the mixture is combined.
Pour the mixture into a large saucepan and cook over medium-low heat for about 5 minutes, stirring constantly with a wooden spoon, until the mixture is very thick. Off the heat, add the chocolate, butter, coffee liqueur and coffee powder and stir until the chocolate is melted. Pour the filling into the cooled tart pan and smooth the top. Place plastic wrap directly on top of the chocolate filling and chill for 6 hours.
When ready to serve, remove the plastic wrap from the chocolate and arrange the banana slices in concentric circles on top of the filling.
Place the heavy cream, sugar and vanilla in the bowl of an electric mixer fitted with the whisk attachment and beat until the cream forms firm peaks. Spoon the whipped cream on top of the bananas and gently spread the cream with a spatula to cover the pie, leaving a border of bananas visible at the outside edge. For a garnish, shave curls of milk chocolate on top of the whipped cream. Remove the pie from the pan, place it on a cake plate and serve.