Preheat the oven to 325°F. Lightly grease a 9-inch springform pan and line the bottom with parchment paper. Wrap the outside tightly with multiple layers of heavy-duty aluminum foil to protect it from the water bath. For extra leak protection, place the wrapped springform pan inside a slightly larger solid pan.

Add the Biscoff cookies, Nilla wafers, cinnamon, granulated sugar, and salt to a food processor. Pulse until it is all combined with fine crumbs. Then add to a medium bowl with the melted butter. Mix until the crumbs are evenly moistened. Press the mixture firmly into the bottom and slightly up the sides of the prepared springform pan. Bake for 8–10 minutes, then remove from the oven and allow to cool while preparing the filling.

Mash the overripe bananas until mostly smooth. Transfer to a small skillet over medium heat and cook for 3–4 minutes, stirring frequently, until the mixture thickens slightly and some excess moisture evaporates. Stir in the optional espresso powder while warm. Remove from heat and allow the banana mixture to cool completely.

In the bowl of a stand mixer fitted with the paddle attachment, beat the fully softened cream cheese on medium speed until completely smooth and free of lumps. Scrape down the sides and bottom of the bowl as needed.

Add the granulated sugar and cornstarch. Mix on low speed until incorporated. Add the cooled banana mixture and continue mixing on low until evenly combined.

Add the sour cream, heavy cream, vanilla bean paste, and cinnamon. Mix on low speed until smooth, scraping down the bowl as necessary.

Add the eggs one at a time, mixing on low speed just until each egg is incorporated before adding the next. Avoid overmixing, as incorporating too much air can cause the cheesecake to rise and crack during baking.

Pour the cheesecake filling over the cooled crust and smooth the top. Place the protected springform pan inside a large roasting pan. Carefully pour hot water into the roasting pan until it reaches approximately halfway up the sides of the springform pan, or the protective outer pan if using one.

Carefully transfer the roasting pan to the oven. Bake at 325°F for approximately 65–75 minutes, until the edges are set and the center still has a slight jiggle. The center should move gently as one piece rather than appear liquid. Avoid overbaking.

Turn off the oven and crack the oven door slightly open. Leave the cheesecake inside for approximately 2 hours to cool gradually. This helps reduce sudden temperature changes that can cause cracks.

Carefully remove the cheesecake from the water bath and discard the foil. Allow it to cool further at room temperature if needed, then refrigerate promptly. Do not leave it at room temperature for more than 2 hours after removing it from the oven.

Refrigerate for at least 4 hours, preferably overnight, until completely chilled and set. Carefully remove the springform ring. Slice with a sharp knife, wiping the blade clean between cuts. Serve chilled, plain or with your favorite toppings.