For the crust: Position an oven rack in the center of the oven and preheat to 350 degrees F. Spray a 6-inch springform pan with cooking spray to coat the bottom and sides.
Add the graham crackers to a resealable plastic bag. Using your hands or a rolling pin, crush the graham crackers into crumbs. Transfer them to a mixing bowl and add the melted butter. Fold and press together with a spatula until a loose, crumbly mixture is made. Pour the mixture into the bottom of the prepared pan and press to create an even base for the cheesecake. Chill the crust in the fridge while you make the filling to set the base.
For the filling: Add the chocolate to a heatproof bowl and set the bowl over a pan of simmering water. Heat, stirring with a spatula, until the chocolate is melted and completely smooth. Set aside.
Mix the cream cheese, sugar and cocoa powder in a food processor until smooth. Remove the lid and scrape down the sides of the bowl. Add the vanilla, salt and egg and process until completely incorporated. Scrape down the sides once more. Turn the machine back on and while the machine is running, drizzle in the melted chocolate and allow it to completely incorporate into the mixture.
Pour the chocolate filling over the prepared crust and smooth out the top with a spatula. Transfer the cheesecake to the center rack and bake until the filling is no longer soupy but still slightly jiggly, about 32 minutes. Turn off the oven and open the door just a hair. Allow the cheesecake to sit in the warm oven for 15 more minutes with the door ajar.
Transfer the cheesecake to a cooling rack and let cool for 30 minutes.
Run a sharp knife around the edge of the pan to help free the cheesecake, but keep it in the pan. The cheesecake will continue to shrink while it cools and this step makes it easier to separate the cheesecake when you are ready to serve it.
For the topping: Pour the cherry pie filling onto the cooled cheesecake and smooth into an even layer, leaving a bit uncovered around the edges. Cover the springform pan with plastic wrap and refrigerate for at least 2 hours.
When you are ready to eat, remove the cheesecake from the fridge and transfer to a serving platter. Garnish with a sprig of mint and serve.