Let the cream cheese come to room temperature and thaw the whipped topping in the refrigerator before beginning. Soft cream cheese blends more smoothly and helps prevent small lumps in the finished filling.

Beat the softened cream cheese and creamy peanut butter together until completely smooth and fully combined. Scrape down the sides and bottom of the bowl so the mixture has an even texture.

Add the powdered sugar and vanilla extract, then beat until the sugar disappears into the mixture. Scrape the bowl again, checking that no cream-cheese lumps remain.

Gently fold in the thawed whipped topping with a spatula until the filling is light and evenly blended. Stop mixing as soon as no visible streaks remain so the filling keeps its volume.

Spoon the peanut butter filling into the prepared graham-cracker crust and smooth the top with an offset spatula or the back of a spoon. Cover the pie carefully so the cover does not touch the surface.

Refrigerate the covered pie for at least 4 hours before slicing, although chilling overnight provides the firmest texture. Add whipped cream, peanuts, chocolate, or peanut butter cups just before serving.