Preheat your oven to 350°F (175°C). In a mixing bowl, blend the graham cracker crumbs with melted unsalted butter until evenly moistened. Press this mixture firmly into the bottom of a 9-inch springform pan. Bake for 10 minutes or until lightly golden, then remove and allow to cool completely.

In a large mixing bowl, beat softened cream cheese until smooth and creamy, then add granulated sugar until well combined. Add the zest and juice of the fresh oranges and mix until velvety.

Melt dark chocolate carefully, let it cool slightly, and fold it into the cream cheese mixture. In a separate bowl, whip the heavy cream until soft peaks form, then fold it into the mixture.

Pour the filling over the cooled crust, smoothing the top. Cover with plastic wrap and refrigerate for at least 4 hours or overnight.

Once set, release the springform pan sides. Drizzle melted dark chocolate over the top and garnish with fresh orange slices for presentation.