Prepare the crust: Preheat the oven to 325°F (163°C). Grease and line the bottom of a 9-inch springform pan with parchment paper. In a medium bowl, combine chocolate cookie crumbs, sugar, and melted butter. Press into the bottom of the pan. Bake for 8-10 minutes, then set aside to cool.

1. Prepare the filling: In a small saucepan, heat the heavy cream over medium heat until simmering. Remove from heat, stir in dark chocolate chips until smooth. In a bowl, beat cream cheese, sugar, and vanilla until smooth. Add eggs one at a time, then stir in sour cream, heavy cream, flour, and salt. Gradually pour in the melted chocolate mixture and combine.
2. Pour the filling over the cooled crust and smooth the top. Bake for 55-65 minutes, or until the edges are set and the center slightly jiggly. Turn off the oven and let the cheesecake cool in the oven for 1 hour, then cool to room temperature. Refrigerate for at least 4 hours or overnight.
3. Prepare the topping: Before serving, top the cheesecake with whipped cream, orange slices or zest, and shaved dark chocolate or a dusting of cocoa powder. Serve chilled.