01 - Preheat oven to 350°F. Grease a 9x13-inch baking dish lightly with butter or cooking spray.
02 - Beat cream cheese and sugar in a medium bowl until completely smooth. Add egg and vanilla extract, mixing until fully combined and creamy. Spread evenly across the bottom of the prepared baking dish.
03 - Arrange sliced bananas in a single layer over the cheesecake mixture, ensuring even coverage.
04 - Whisk instant banana pudding mix with cold milk for 2 minutes until mixture thickens considerably. Pour over the banana slices and spread gently to create an even layer.
05 - Sprinkle coarsely crushed vanilla wafer cookies uniformly over the pudding layer.
06 - Evenly distribute the dry yellow cake mix over the crushed wafers. Do not stir or mix the layers.
07 - Drizzle melted butter across the entire surface of the cake mix, covering as much of the dry mix as possible.
08 - Bake for 45 to 50 minutes until the top turns golden brown and the center appears mostly set. The surface should be slightly crisp but still yield to gentle pressure.
09 - Allow the cake to cool at room temperature for at least 30 minutes before serving. This helps the layers set properly.
10 - While the cake cools, whip the heavy cream with powdered sugar and vanilla extract until soft peaks form. Do not overbeat.
11 - Serve the dessert warm or refrigerated until fully chilled. Top portions with freshly whipped cream, additional banana slices, and extra vanilla wafers as desired.