Add contents of pudding mix to a large mixing bowl. Add milk and whisk until the mixture is smooth. Let the pudding mixture sit for a couple of minutes to thicken.
Slice bananas and coarsely crush vanilla wafers
Blend Cool Whip into the pudding mixture. Fold in bananas and crushed cookies.
Scoop banana pudding into jars or dessert cups. When ready to serve, top with additional banana slices and vanilla wafers.