For the crust:
Preheat the oven to 325°F (163°C). In a food processor, pulse the graham crackers until you have 1 cup of finely ground crumbs.
Add the melted butter and pulse until the crumbs are moistened.
Press the mixture into the bottom and halfway up the sides of a 9-inch springform pan.
Bake for 10 minutes or until fragrant. Let cool slightly while maintaining the oven temperature for the filling.
For the filling:
In a microwave-safe bowl, melt the chopped semisweet chocolate in 30-second intervals, stirring between each, until smooth. Let it cool.
In the bowl of an electric mixer, beat the cream cheese for 1 minute until smooth.
Add the sugar, heavy cream, and cocoa powder, and beat until combined.
Scrape down the sides of the bowl to ensure all the cream cheese is incorporated.
Add the eggs one at a time, beating just until smooth after each addition. Be careful not to overbeat.
Stir in the melted chocolate until just combined.
Pour the cheesecake filling into the cooled crust. Place the springform pan on a rimmed baking sheet to catch any drips.
Bake for 50 minutes, or until the top looks slightly dry and the center is slightly wobbly. Avoid overbaking.
Turn off the oven, crack the oven door, and let the cheesecake cool in the oven for 10 minutes to help prevent cracks.
Remove the cheesecake and place it on a wire rack to cool to room temperature.
Refrigerate for at least 4 hours until fully chilled. Release the cheesecake from the springform pan and transfer it to a serving plate.
For the topping:
Place the chocolate chips in a heatproof bowl.
In a small saucepan, heat the cream until just simmering.
Pour the hot cream over the chocolate chips and let it sit for 3 minutes.
Stir until the chocolate is melted and the mixture is smooth. If the ganache is too runny, allow it to cool and thicken slightly.
Pour the chocolate ganache over the chilled cheesecake, allowing it to drip down the sides.