Step 1: Prepare the Crust
Preheat the oven to 325°F (163°C). Line the bottom of a 9-inch springform pan with parchment paper.

Crush the Nilla wafers in a food processor or place them in a ziplock bag and crush with a rolling pin until fine.

Combine the crushed cookies, sugar, and melted butter in a bowl. Mix until the crumbs are evenly moistened.

Press the mixture into the bottom of the pan in an even layer. Bake for 10 minutes, then remove from the oven and let it cool while you make the filling.

Step 2: Set Up the Water Bath
Boil a large pot of water. You’ll use this for the water bath to help the cheesecake bake gently and prevent cracks.

Wrap the springform pan in foil to keep water from seeping in during baking. Set the pan aside while you prepare the filling.

Step 3: Make the Filling
In a large mixing bowl, beat the softened cream cheese on low-medium speed until completely smooth (about 1–2 minutes).

Add the mashed banana and sour cream and mix until well combined, scraping down the sides of the bowl as needed.

Add the sugar, banana pudding mix, and vanilla extract. Beat until smooth and fully incorporated (about 30–60 seconds).

In a separate bowl, lightly beat the eggs. Add them to the cream cheese mixture and mix on low speed until just combined. Do not overmix.

Step 4: Assemble and Bake
Pour the filling into the cooled crust and smooth the top with a spatula.

Place the wrapped pan into a large roasting pan. Carefully pour boiling water into the roasting pan until it reaches about halfway up the sides of the cheesecake pan.

Bake at 325°F (163°C) for 55–70 minutes. The edges should be set, and the center should still have a slight jiggle.

Turn off the oven and crack the door open. Let the cheesecake cool inside for 1 hour, then transfer to the fridge to chill for at least 6 hours, preferably overnight.

Step 5: Add Toppings and Serve
Once chilled, remove the cheesecake from the springform pan and transfer to a serving plate.

Top with whipped cream, banana slices, and extra Nilla wafers if desired. Slice with a sharp knife and serve cold.

Store leftovers in the refrigerator for up to 5 days.