Using a stand mixer fitted with the whisk attachment, or in a large mixing bowl using an electric mixer, beat the cream cheese until smooth. Add in the peanut butter, powdered sugar, and vanilla extract and mix until fully combined.
In a separate mixing bowl, beat the heavy whipping cream with an electric mixer until stiff peaks form. Add the whipped cream to the peanut butter cream cheese mixture and mix it in on low speed until just combined (or gently fold it in with a rubber spatula).
Remove the crust from the refrigerator, pour the filling over the pie crust, and spread it around into one even layer.
Cover and return to the refrigerator to chill for at least 4-5 hours or overnight. Once chilled top with whipped cream and peanut butter cups if desired. Cut into slices, serve, and enjoy!