Make the Filling
In a large bowl, beat the softened cream cheese and peanut butter together until smooth. Add powdered sugar and vanilla extract, and mix well. Gently fold in the whipped topping until fully combined. Set aside.

Dip the Cookies
Pour milk into a shallow bowl. Lightly dip each Nutter Butter cookie in the milk for 1–2 seconds per side to soften slightly.

Assemble the Layers
In a 9×13-inch dish, place a layer of dipped cookies on the bottom. Spread a layer of the peanut butter filling over the cookies. Repeat layers until you finish the filling, ending with a layer of the cream mixture on top.

Chill
Cover and refrigerate the cake for at least 4 hours or overnight for best results.

Garnish and Serve
Just before serving, top with crushed Nutter Butters and a drizzle of peanut butter or chocolate, if desired.