Preheat oven to 350 degrees.
For crust, stir together crushed cookies, butter and salt in a medium bowl. Using the bottom of a measuring cup, press mixture into bottom and up sides of a 9-inch pie plate. Bake until light golden brown, approximately 10 minutes. Transfer to a wire rack, let cool.
For filling, place sliced bananas in bottom of cooled crust. Set aside.
In a medium saucepan, combine brown sugar, cornstarch and salt; whisk in milk and egg yolks until combined. Cook over medium heat, stirring constantly, until thickened, approximately 10 minutes. Remove from heat. Stir in butter and vanilla.
Spoon filling over banana in crust. Let cool 10 minutes. Place a piece of plastic wrap directly on surface of filling. Refrigerate until firm, approximately 3 hours. Spread with whipped topping; garnish with whole cookies around edges and crumbs on top, if desired.