In a medium bowl, combine the peanut butter cookie crumbs and melted butter. Mix until the crumbs are evenly coated.
Press the crumb mixture firmly into the bottom of an 8×8 inch square dish to form the base layer. Place in the refrigerator to chill while preparing the filling.
In a large bowl, beat the cream cheese and peanut butter together until smooth and creamy using an electric mixer on medium speed.
Add the powdered sugar and vanilla extract to the peanut butter mixture. Beat until fully combined and smooth.
In a separate chilled bowl, whip the heavy cream and granulated sugar on high speed until stiff peaks form.
Gently fold the whipped cream into the peanut butter mixture until well combined and fluffy.
Spread the peanut butter filling evenly over the chilled cookie crumb base.
Cover the dish with plastic wrap and refrigerate for at least 4 hours or until set.
Before serving, optionally garnish with additional crushed peanut butter cookies or a drizzle of peanut butter.