Preheat your oven to 325°F (163°C). Line the bottom of a 9-inch springform pan with parchment paper and grease the sides. Combine the vanilla wafer crumbs, sugar, and melted butter in a bowl. Press the mixture firmly into the bottom and up the sides of the pan. Bake for 8-10 minutes, then set aside to cool.

Once the pan is cool, wrap the outside securely with multiple layers of heavy-duty aluminum foil to prevent water from leaking in.

Reduce the oven temperature to 300°F (148°C). In a large mixing bowl, beat the cream cheese, sugar, flour, and dry banana pudding mix on low speed until the mixture is smooth. The batter will be thick and sticky at this stage.

Add the sour cream and mix on low speed until combined. Add the eggs one at a time, mixing slowly after each addition and scraping down the sides of the bowl to ensure a uniform consistency.

Gently mix in the mashed bananas and vanilla extract on low speed. Note that the mixture may appear slightly lumpy due to the fresh fruit.

Pour the batter into the prepared crust. Place the springform pan inside a larger roasting pan and fill the outer pan with warm water until it reaches halfway up the sides of the cheesecake pan. Bake for 1 hour and 30 to 45 minutes. The edges should be set, but the center should still have a slight jiggle.

Turn off the oven and leave the door closed for 30 minutes. Then, crack the oven door open slightly and let the cheesecake sit for another 30 minutes. This gradual cooling prevents cracks.

Remove the cheesecake from the water bath and refrigerate for at least 5-6 hours, or preferably overnight, until firm.

Before serving, whip the heavy cream, powdered sugar, and vanilla extract until stiff peaks form. Arrange sliced bananas on top of the chilled cheesecake, pipe the whipped cream over the fruit, and garnish with whole vanilla wafers for that signature crunch.