01 - Preheat oven to 350°F. Grease a 9x13-inch baking dish lightly with butter or cooking spray.
02 - In a medium bowl, beat cream cheese with granulated sugar until completely smooth. Add egg and vanilla extract, mixing until fully incorporated and creamy. Spread evenly across the bottom of the prepared baking dish.
03 - Arrange sliced bananas in a single, even layer over the cheesecake mixture.
04 - In a separate bowl, whisk together instant banana pudding mix and cold milk for 2 minutes until mixture thickens noticeably. Pour over the banana layer and spread gently to create an even surface.
05 - Sprinkle crushed vanilla wafer cookies evenly over the pudding layer, covering completely.
06 - Evenly distribute dry yellow cake mix over the wafer layer. Do not stir or mix the layers.
07 - Drizzle melted butter over the cake mix, aiming to cover as much surface area as possible for even baking.
08 - Bake for 45 to 50 minutes until the top turns golden brown and the center appears mostly set. The cake will continue to set as it cools.
09 - While cake bakes, whip cold heavy cream with powdered sugar and vanilla extract using an electric mixer or whisk until soft peaks form.
10 - Let the cake cool for at least 30 minutes before serving. Serve warm for a gooier texture or chilled for a firmer consistency. Top with whipped cream, additional banana slices, and extra vanilla wafers if desired.