01 - Preheat oven to 350°F. Grease a 9x13-inch baking dish thoroughly with butter or cooking spray.
02 - Beat cream cheese with granulated sugar in a medium bowl until completely smooth. Add egg and vanilla extract, mixing until creamy and well combined. Spread evenly in the bottom of the prepared baking dish.
03 - Arrange sliced bananas evenly over the cheesecake layer, creating a solid fruit base.
04 - Whisk together instant banana pudding mix and cold milk in a separate bowl for 2 minutes until thickened. Pour over the banana layer and gently spread to cover evenly.
05 - Sprinkle crushed vanilla wafers evenly over the pudding layer.
06 - Evenly sprinkle the dry yellow cake mix over the wafer layer. Do not stir or mix.
07 - Drizzle melted butter over the cake mix, covering as much surface area as possible.
08 - Bake for 45–50 minutes, or until the top is golden brown and the center is mostly set. Remove from oven and cool for at least 30 minutes.
09 - While cake cools, whip heavy cream with powdered sugar and vanilla extract until soft peaks form.
10 - Serve the dump cake warm or chilled, topped with fresh whipped cream, additional banana slices, and extra vanilla wafers if desired.