01 - Preheat oven to 350°F. Grease a 9x13-inch baking dish.
02 - In a medium bowl, beat cream cheese with sugar until smooth. Add egg and vanilla extract, mixing until creamy. Spread evenly in the bottom of the prepared baking dish.
03 - Arrange sliced bananas evenly over the cheesecake layer.
04 - In another bowl, whisk together banana pudding mix and cold milk for 2 minutes until thickened. Pour over the banana layer and gently spread.
05 - Sprinkle crushed vanilla wafers evenly over the pudding.
06 - Evenly sprinkle the dry yellow cake mix over the top. Do not mix.
07 - Drizzle melted butter over the cake mix, covering as much as possible.
08 - Bake for 45–50 minutes, or until the top is golden and the center is mostly set. Cool for at least 30 minutes.
09 - Meanwhile, whip heavy cream with powdered sugar and vanilla extract until soft peaks form.
10 - Serve the dump cake warm or chilled, topped with whipped cream, banana slices, and extra wafers if desired.