Prep the pan: Line an 8x8- or 9x9-inch square pan with parchment, letting it hang over the edges for easy lifting. Lightly grease the sides.
Make the crust: Pulse vanilla wafers or grahams into fine crumbs.
Mix with melted butter and sugar until the texture feels like wet sand. Press firmly into the pan in an even layer. Chill for 10–15 minutes while you make the filling.
Whisk the pudding: In a large bowl, whisk instant pudding mix with cold milk for 2 minutes until thickened.
Let it sit for another 2–3 minutes.
Beat the cream cheese layer: In a separate bowl, beat softened cream cheese until smooth. Add sweetened condensed milk and vanilla, and beat until silky with no lumps.
Fold in the pudding: Gently fold the thickened pudding into the cream cheese mixture. Aim for a smooth, fluffy consistency.
Slice the bananas: Cut bananas into 1/4-inch coins.
Pat gently with a paper towel if very moist to prevent slipping layers.
Layer it up: Spread half the cream layer over the chilled crust. Add a single layer of banana slices. Top with the remaining cream layer and smooth the surface.
Add the topping: Spread whipped topping evenly over the cream layer.
If you like, sprinkle crushed cookies or a light dusting of cinnamon on top.
Chill to set: Cover and refrigerate for at least 4 hours, preferably overnight. This helps the bars slice cleanly and the flavors meld.
Slice and serve: Lift out using the parchment overhang. Cut into bars with a sharp, clean knife.
Wipe the blade between cuts for neat slices. Garnish with fresh banana slices right before serving if desired.