Add vanilla wafers and peanuts to the bowl of a food processor. Pulse until coarse crumbs have formed.
Combine crumbs with melted butter, mixing until moistened.
Press crumb mixture firmly into a 13x9-inch pan to form crust. Bake for 8-10 minutes or until golden-brown. Set aside and let cool.
In the bowl of a stand mixer fitted with the paddle attachment (or in a large mixing bowl with a handheld electric mixer), beat together cream cheese, powdered sugar, and peanut butter until smooth.
Gradually beat in two cups of whipped topping until fully incorporated. Spread the mixture over the cooled crust.
In a separate mixing bowl, combine the milk and dry pudding mix. Whisk together for 2 minutes.
Add 1 cup of whipped topping to the pudding mixture, folding in by hand until no streaks remain. Spread mixture over the peanut butter layer in the pan.
Spread the remaining whipped topping over the pudding mixture, then cover and refrigerate for 4-6 hours before serving.
Notes
If desired, you can garnish the top of the dessert with crushed peanuts, chopped Butterfinger candy or Reeses cups, or chocolate shavings.
Keep refrigerated until serving, and refrigerate any leftovers for up to 3-5 days.