Preheat the oven to 350°F (175°C).
Mix graham cracker crumbs, melted butter, and sugar until combined.
Press the mixture firmly into the bottom of a 9-inch springform pan.
Bake for 8–10 minutes, then let it cool completely.
Make the Filling:
Reduce oven temperature to 325°F (160°C).
In a large bowl, beat the cream cheese and sugar until smooth and creamy.
Add eggs one at a time, mixing after each addition.
Stir in the melted chocolate, cocoa powder, and vanilla extract until well blended.
Bake the Cheesecake:
Pour the filling over the cooled crust and smooth the top.
Bake for 50–60 minutes, or until the center is just set but still slightly jiggly.
Turn off the oven, crack the door open slightly, and let the cheesecake cool inside for 1 hour to prevent cracks.
Chill and Serve:
Refrigerate for at least 4 hours or overnight for best texture.
Before serving, top with whipped cream or chocolate shavings if desired.
