Preheat your oven to 325°F (160°C). Combine Nilla Wafers, brown sugar, and melted unsalted butter until mixed. Press into a greased springform pan and bake for 11 minutes. Let cool.

In a large bowl, beat cream cheese and granulated sugar until smooth. Add mashed bananas, vanilla extract, sour cream, and heavy cream, mixing until incorporated. Fold in eggs gently.

Pour half of the cheesecake filling into the cooled crust. Layer with sliced bananas and crushed Nilla Wafers, then add the remaining filling on top.

Place the springform pan in a larger roasting pan and fill with hot water halfway up the sides. Bake the cheesecake for 80-90 minutes.

Turn off the oven and crack the door, allowing the cheesecake to cool in the oven for 30 minutes. Remove from the water bath, cover, and refrigerate for at least 6 hours or overnight.

Whisk together instant pudding mix and cold milk until thickened. Fold in whipped cream to create the topping.

Carefully remove the cheesecake from the springform pan. Spread the pudding topping over the surface and sprinkle with crushed Nilla Wafers. Serve chilled.