In a food processor, process the butter and cookies until cookies are fine crumbs and the mixture starts to stick together.
Place a piece of parchment paper in between the bottom and the rim of a 9" springform pan (optional -- just helps to remove the cheesecake later).
Press the crust mixture firmly into the bottom of the pan and about ½" up the sides. Set aside.
In a medium bowl, combine chocolate and ½ cup cream. Microwave in 20-30 second intervals on high, stirring well each time, until melted and smooth. Set aside to cool slightly.
In a large bowl, beat the cream cheese with an electric mixer until smooth. Add the powdered sugar and melted chocolate, and beat on low speed until combined.
In a separate bowl, whip the cream until stiff peaks form. Fold into the cream cheese mixture with a spatula or an electric mixer on low.
Spread into the prepared crust, cover, and refrigerate for at least 6 hours or overnight. Slice and serve with whipped cream or as desired.
