In a food processor (or with a zip lock bag and a little aggression) pulse the Oreo cookies until crumbled. Mix in the melted butter and pulse once or twice. Press the cookie mixture into a pie plate and freeze for at least 20 minutes before proceeding.
In a small saucepan over medium heat, combine the cream and peanut butter and cook until smooth, stirring often. Mix in the confectioners sugar. (If it becomes too thick while adding the confectioners sugar, set over heat again for a minute). Set aside to cool to room temperature.
Once cooled, fold the whipped cream into the peanut butter mixture. Once combines, fold in the mini peanut butter cups. Spoon mixture into the prepared pie plate and top with Reese’s Pieces candy. Freeze for 3 hours or overnight before serving. Let pie sit for 10 minutes at room temperature before trying to slice into it.