Beat softened cream cheese and peanut butter until smooth.
Add powdered sugar and vanilla extract to the peanut butter mixture and beat until incorporated.
In a separate chilled bowl, whip heavy cream until firm peaks form.
Gently fold the whipped cream into the peanut butter mixture until uniform.
Arrange a layer of graham crackers in the bottom of a rectangular dish.
Spread a thin layer of the peanut butter filling over the crackers.
Repeat layering crackers and filling until ingredients are used.
Refrigerate for at least 6 hours until the crackers soften and the cake sets.