Black-Bottom Banana Dream Bars - crust

Method

• Grease a 9-in-by-9-in [23-cm-by-23-cm] pan with nonstick cooking spray or softened butter. Place a piece of parchment paper on the bottom of the pan and up two sides, grease the paper, and set aside.
• For the crust, place the wafers and granulated sugar in the bowl of a food processor fitted with the metal blade and process until finely ground. Add the melted butter and process until combined, scraping down the bowl with a rubber spatula, if needed. Transfer the crumbs to the prepared pan and, using your fingers, press them evenly on the bottom of the pan. Freeze for at least 30 minutes or up to 3 days, tightly covered in plastic wrap.
• Preheat the oven to 350°F [180°C].
• Bake the crust for 8 to 10 minutes, rotating at the halfway point, until it is dry to the touch and slightly puffy. Let cool completely.
• For the topping In the bowl of a stand mixer fitted with the paddle attachment, beat the eggs and vanilla on medium-high speed until quite frothy, at least 5 minutes. Add the brown sugar and beat again for 5 minutes. Remove the bowl from the mixer and, using a wire mesh sieve, sift the flour, baking powder, and salt over the bowl. Gently fold the dry ingredients into the wet with a rubber spatula. Gently fold in the walnuts, coconut, bananas, and chocolate chips.
• Pour the topping over the crust and spread evenly. Bake for 20 to 25 minutes, rotating at the halfway point, until the top is nicely browned, looks set, and is no longer wet.
• Let the bars come to room temperature and refrigerate until cold (this will make slicing the bars easier). Serve cold or at room temperature. The bars will keep in the refrigerator, tightly wrapped in plastic wrap, for up to 3 days.