01 - Preheat oven to 325°F. Grease a 9-inch springform pan and line the base with parchment paper.
02 - Combine crushed chocolate sandwich cookies with melted butter until evenly moistened. Press the mixture firmly into the base of the prepared pan. Bake for 10 minutes, then set aside to cool slightly.
03 - Using an electric mixer, beat the softened cream cheese and granulated sugar on medium speed until completely smooth and free of lumps. Blend in the creamy peanut butter and sour cream until uniformly combined.
04 - Add eggs one at a time, mixing on low speed after each addition until just incorporated. Stir in the vanilla extract. Avoid overmixing to prevent excess air in the batter.
05 - Pour half of the filling over the cooled crust. Drizzle half of the melted dark chocolate over the batter and gently swirl with a butter knife. Add the remaining batter and repeat with the remaining melted chocolate, creating a marbled effect.
06 - Bake for 50 to 55 minutes, until the edges are set but the center still has a slight jiggle. Turn off the oven, crack the door open, and allow the cheesecake to cool gradually inside for 1 hour.
07 - Remove the cheesecake from the oven and transfer to the refrigerator. Chill for at least 4 hours or preferably overnight to fully set.
08 - Heat the heavy cream in a small saucepan until hot but not boiling. Pour over the chopped dark chocolate and let stand for 2 minutes. Stir until smooth and glossy, then blend in the peanut butter. Spread the ganache evenly over the chilled cheesecake and let set for at least 30 minutes before slicing.