Start by spraying a 9-inch pie pan with nonstick spray. In a food processor, pulse whole Oreo cookies into fine crumbs, then mix in melted unsalted butter. Press the mixture into the pie pan and place in the freezer for at least 15 minutes.

In a mixing bowl, beat cream cheese with sugar and cocoa powder on high speed until smooth. Slowly incorporate vanilla extract and sour cream, then add melted chocolate until rich and uniform.

In another bowl, beat cream cheese with sugar until fluffy, then mix in peanut butter, vanilla extract, and remaining sour cream until smooth.

In a cold metal bowl, whip heavy cream and powdered sugar until stiff peaks form, about 3-5 minutes. Be careful not to overmix.

Gently fold half of the whipped cream into the chocolate mixture, then fold the remaining whipped cream into the peanut butter mix.

Spread the chocolate layer over the crust, then layer the peanut butter mixture on top. Drizzle melted peanut butter and swirl with a knife.

Cover the pie with foil and refrigerate for at least 6 hours or overnight. This helps the layers set.

Before serving, decorate the pie with chopped peanut butter cups. Use a warm knife to slice cleanly.