BANANA PUDDING CHEESECAKE BARS

Steps:

• Crust
• Place a rack in middle of oven; preheat to 325°F. Line a 13x9" or 12x8" baking pan with two pieces of parchment paper, leaving overhang on all sides. Anchor parchment to pan with metal binder clips. Stir Nilla wafers, sugar, salt, and remaining 4 Tbsp. butter in a medium bowl to combine. Press mixture into an even layer in bottom of prepared pan; it won't hold together but will pack like a sand. Bake until toasted, about 10 minutes. Let cool.
• Filling and assembly
• While the crust is cooling, beat cream cheese in the bowl of a stand mixer fitted with the paddle attachment on medium-high speed, stopping motor occasionally and scraping down sides of bowl and beater, 3 minutes. Reduce speed to medium and drop in pieces of banana, a little at a time, breaking up and incorporating completely before adding more. (Adding the bananas slowly helps blend them into the cream cheese.) Scrape down bowl and beater again, then beat 2 minutes on medium-high, covering mixer with a splash guard or kitchen towel to avoid spatter. Reduce speed to medium-low and pour in condensed milk; beat, scraping down bowl halfway through, 2 minutes. Reduce speed to low and add eggs, one at a time, mixing well after each addition; mix in salt. For the silkiest cheesecake, strain filling though a fine-mesh sieve into a jug or pitcher, pushing through with a rubber spatula. Stir in vanilla paste or scrape in vanilla seeds and mix well.
• Knock stand mixer bowl or jug against counter a few times to release any trapped air. Let filling sit 2 minutes, then pour into crust. Bake cheesecake until 2" of edges are puffed and center wobbles slightly when pan is gently shaken, 30-35 minutes, depending on size of pan. Turn off oven and prop open door (a wooden spoon works well). Let cheesecake cool in oven 30 minutes. Transfer pan to a wire rack and let cheesecake cool completely. Chill until cold, at least 4 hours, covering with wax paper or plastic wrap after 1 hour.
• When you are ready to top cheesecake, beat heavy cream, sour cream, and powdered sugar in the clean bowl of a stand mixer with whisk attachment on medium-high until stiff peaks form, about 5 minutes. Spread topping over chilled cheesecake. Chill, uncovered, at least 1 hour before serving.
• Slice cheesecake with a hot, dry knife and serve cold or room temperature. Do ahead: Cheesecake can be made 1 week ahead. Cover and keep chilled, or freeze up to 1 month. Crust will be slightly softer than when freshly made.