Crush graham crackers into fine crumbs using a food processor or blender.
Mix graham cracker crumbs with melted butter and 1/2 cup powdered sugar to form a crust.
Press the mixture firmly into the bottom of a 9×13-inch baking pan, creating an even layer.
In a bowl, beat cream cheese until smooth and creamy.
Gradually mix in sweetened condensed milk and vanilla extract until fully incorporated.
Spread the creamy filling over the crust and smooth the surface.
Peel and slice bananas; arrange them evenly over the filling.
Refrigerate for at least 4 hours or until the filling sets.
Before serving, frost the top with whipped cream.
Cut into 16 bars and serve chilled.