Add the chocolate wafer cookies to the bowl of a food processor. Pulse until the cookies have turned into crumbs.
With the food processor running, drizzle in the melted butter and process until well combined.
Pour the crumbs into the tart pan. Using the bottom of a measuring cup, press the crumbs firmly into the pan and up the sides. Chill the crust for 30 minutes.
For the filling, add the softened cream cheese and peanut butter to the bowl of a stand mixer. Cream together until smooth and well combined. Add the powdered sugar, salt, and vanilla extract and mix until light and creamy, approx. 2-3 minutes.
Add 1/3 of the whipped topping and mix thoroughly to lighten up the peanut butter mixture. Gently fold in the remaining whipped topping until combined.
Spoon the filling into the crust and spread evenly. Chill the tart for 4 hours or until firm.
Garnish with chocolate syrup and chopped peanut butter cups. Store, covered, in the refrigerator for up to 1 week.