Step 5: Fold the Mixtures: Gradually add your dry flour mixture into the wet banana bowl. Mix gently on low speed or use a spatula to fold the ingredients together just until the flour streaks disappear.
A Friendly Kitchen Note: Stop mixing the split second the batter is uniform! Over-working a heavy pound cake batter develops excess gluten in the flour, which will transform your soft, tight-crumbed velvet cake into a tough, unpleasantly rubbery, and heavy texture.
Step 6: The Long Golden Bake: Pour the thick batter into your prepared pan, smoothing out the top surface with a spatula. Slide it onto the center rack of your oven and bake for 55 / to 65 / minutes. You’ll know it is perfectly ready when a toothpick inserted into the deepest center point of the cake comes out completely clean and the top crust is a rich golden-brown color.
Step 7: The Cooling Window: Remove the pan from the oven and let the cake sit completely undisturbed in its pan for 15 / minutes to allow the structure to settle. Carefully invert the cake onto a wire cooling rack to slide it free, and let it cool completely to room temperature before assembling.
Step 8: Cook the Scratch Custard: While the cake cools, build your banana pudding base. In a saucepan over medium heat, combine the whole milk, 1/2 / cup of granulated sugar, the cornstarch, and 1/4 / teaspoon of salt. Cook, stirring continuously with a whisk, until the mixture thickens up significantly and begins to bubble. Remove the saucepan from the heat source.
Step 9: Temper the Egg Yolks: In a separate small bowl, whisk the 3 large egg yolks. Slowly drizzle a few tablespoons of the hot milk mixture into the egg yolks while whisking vigorously to “temper” them, preventing them from scrambling. Pour the warmed egg yolk mixture back into the main saucepan. Place it back over medium heat and cook, stirring constantly, for an additional 2 / minutes to thicken. Remove from the heat and stir in the 2 / tablespoons of unsalted butter and 1 / teaspoon of vanilla extract. Let the custard cool slightly.
Step 10: Stack and Assemble: Once the pound cake is entirely cool, use a long serrated knife to carefully slice it horizontally into uniform layers. Spread a generous, thick layer of your warm scratch pudding over the bottom cake slice, followed by a flat layer of fresh sliced bananas. Top with the next layer of cake and repeat the process until all layers are stacked.
Step 11: Chill and Set: Spread a generous blanket of whipped cream across the top of the assembled cake. Garnish with additional fresh banana slices and a heavy scatter of crushed vanilla wafers if using. Transfer the completed cake to the refrigerator and chill for at least 1 / hour before slicing to allow the custard to set firmly and fuse with the cake crumb!
