01 - Preheat oven to 350°F. Grease a 9x13-inch baking dish with butter or cooking spray.
02 - Beat cream cheese and sugar until smooth. Add egg and vanilla, mixing until fully combined and creamy. Spread evenly in the bottom of the prepared baking dish.
03 - Arrange sliced bananas in a single, even layer over the cheesecake mixture.
04 - Whisk banana pudding mix and cold milk for 2 minutes until thickened. Pour over the bananas and spread gently to cover.
05 - Sprinkle crushed vanilla wafers evenly over the pudding layer.
06 - Evenly distribute the dry yellow cake mix over the wafers. Do not stir or mix layers.
07 - Drizzle melted butter over the cake mix, covering as much surface area as possible. Bake for 45-50 minutes until golden brown and center is mostly set. Cool for at least 30 minutes.
08 - While cake cools, whip heavy cream with powdered sugar and vanilla extract until soft peaks form.
09 - Serve warm or chilled, topped with whipped cream, additional banana slices, and extra vanilla wafers if desired.