Preheat your oven to 350°F (175°C). In a mixing bowl, combine crushed chocolate cookies with melted butter until the mixture resembles wet sand. Press firmly into a 9-inch pie pan, bake for 10 minutes, then cool completely.

In a large mixing bowl, beat together peanut butter, powdered sugar, and vanilla extract until smooth. Spread evenly over the cooled crust.

In a saucepan, warm heavy cream until simmering. Remove from heat, add chocolate chips, and stir until smooth. Pour over the peanut butter layer.

Using a skewer or knife, swirl the ganache into the peanut butter filling for a marbled effect. Chill in the refrigerator.

Allow the pie to chill in the refrigerator for at least 2 hours.

Before serving, sprinkle chocolate shavings on top and cut with a warm knife for neat slices.