Place both chocolates into a medium bowl. Pour 1/2 cup of the heavy cream into a glass measuring cup, and heat in the microwave until it just begins to simmer. Pour hot cream over the chocolate, cover with plastic wrap, and allow it to sit for a few minutes. Remove the plastic wrap, add the espresso powder, and stir until smooth. Set aside.
In the chilled bowl of a stand mixer fitted with the whisk attachment, whip the remaining 1 cup of heavy cream on high until stiff peaks form. Transfer whipped cream to a separate bowl and keep in the refrigerator.
Switch whisk attachment out for the paddle attachment. Beat the cream cheese on high until smooth and creamy. Add the sugar, vanilla and salt, and continue beating until incorporated. Add the melted chocolate-cream mixture, beating until combined. Fold in the whipped cream until just combined.
Pour filling into the crust, smoothing the surface with an offset spatula or a butterknife. Cover and refrigerate for at least 8 hours, preferably overnight.