For the chocolate crust:

1. Preheat oven to 350ºF/180°C.
2. Mix crumbs with butter until it looks like wet sand.
3. Place mixture in a 9-inch pie pan with removable bottom. Carefully press evenly against bottom and sides of the pan.
4. Bake for 10 minutes. Let cool on a wire rack completely. Alternatively, refrigerate until ready to fill. 

For the chocolate cheesecake filling: 

1. In a large mixing bowl, beat the softened cream cheese with the sugar until smooth and lump-free. You can use an electric mixer for this part. 
2. Add the warm melted chocolate and vanilla and mix to incorporate well. 
3. Beat cold cream in another large bowl until it forms medium-firm peaks.
4. Add the whipped cream to the chocolate mixture in 2 parts, mixing lightly the first time and making sure it's fully incorporated the second time. Don't beat or overmix, but make sure no streaks remain. Use a rubber spatula to integrate well. 
5. Fill the prepared crust, smooth the top and refrigerate the pie for several hours until firm. The pie should be served cold. 

For the whipped cream topping:

1. Beat the cold cream with the powdered sugar in a medium bowl until firm. Be careful not to overheat it as it will start to curdle. 
2. Put the cream in a piping bag with a star or round tip. Pipe mounds in the center of the pie or around the pie. Sprinkle with shaved chocolate and serve.