Prepare the Crust:

1. Preheat oven to 325°F (163°C). Grease a 9-inch springform pan and line the bottom with parchment paper.
2. In a medium bowl, mix vanilla wafer crumbs and granulated sugar. Stir in melted butter until the mixture resembles wet sand.
3. Press the mixture firmly into the bottom and halfway up the sides of the pan.
4. Bake for 10 minutes, then let cool slightly.

Prepare the Cheesecake Filling:

5. In a large mixing bowl, beat softened cream cheese on medium-high speed until creamy (about 2 minutes).
6. Add granulated sugar and flour, mixing until well combined.
7. Mix in dry banana pudding mix until fully incorporated.
8. Add sour cream and vanilla extract, mixing on low speed until combined.
9. Add eggs one at a time, mixing on low speed after each addition until just combined.
10. Gently fold in mashed bananas.

Assemble the Cheesecake:

11. Pour half of the cheesecake filling over the pre-baked crust.
12. Arrange a layer of sliced bananas over the filling, then sprinkle with crushed vanilla wafers.
13. Pour the remaining cheesecake filling over the banana layer, smoothing the top.

Bake the Cheesecake:

14. Place a large roasting pan on the lower oven rack and fill it halfway with hot water to create steam.
15. Place the cheesecake on the middle rack above the water bath.
16. Bake for 70-75 minutes, or until the center is set but slightly jiggly.
17. Turn off the oven, crack the door open, and let the cheesecake cool in the oven for 1 hour.
18. Remove from oven, cool to room temperature, then refrigerate for at least 4 hours or overnight.

Prepare the Whipped Topping:

19. In a bowl, beat cold heavy whipping cream, powdered sugar, and vanilla extract on high speed until stiff peaks form.

Serve:

20. Remove the chilled cheesecake from the springform pan and transfer it to a serving platter.
21. Spread or pipe the whipped topping over the cheesecake.
22. Garnish with whole vanilla wafers and banana slices, if desired.
23. Slice and enjoy!