— 1 cup full fat sour cream
— 1/2 cup full-fat milk
— 1/3 cup vegetable oil
— 3 large eggs
— 1 (15.25 oz) box vanilla
— 1 (3 ounces) box cook and serve banana cream pudding mix (not instant)
— 8 ounces full-fat cream cheese, at room temperature
— 1 1/4 cup powdered sugar
— 2 teaspoons of vanilla extract
— 3 cups cold heavy cream
— 1 (11 ounces) carton Nella Wafer, divided
— 2 medium ripe bananas (but not sliced)
Make the cake: Place 8 ounces of cream cheese for garnishing in the bowl of a stand mixer and let stand at room temperature while making the cake.) Arrange a rack in the middle of the oven and preheat the oven to 350 °F. Coat two (9-inch) round trays with cooking spray, then cover the bottom with parchment paper.
Place 1 cup whole sour cream, 1/2 cup whole milk, 1/3 cup vegetable oil, and 3 large eggs in a large bowl and whisk until smooth. Add one box of cake mix and one box of banana cream pudding mix and beat until smooth. Divide the mixture evenly among the prepared baking trays.
Bake the cake until it turns light brown and a toothpick comes out clean, 20 to 25 minutes. Place the pans on a wire rack and let them cool completely. Meanwhile, make the decorations.
Making the decorations: Add 1 1/4 cups of powdered sugar and 2 teaspoons of vanilla extract to the bowl of cream cheese. Beat with the paddle attachment attached on medium speed until smooth, 3 to 4 minutes. Reduce mixer speed to low and gradually pour in 3 cups of cold heavy cream. Continue whisking until mixture thickens and becomes smooth, about 4 minutes. Increase speed to medium and whisk until garnish is light, fluffy, and doubled in size, 1 to 2 minutes. Transfer 1 cup of frosting to a small zip-top bag and set aside.
Assemble the cake: Place 3 1/2 cups of Nilla Wafers in a large zip-top bag. Seal the bag and gently crush the flakes with a rolling pin or the bottom of the pan to coarse crumbs. Peel a medium-ripe banana (but not sliced) and cut it into thin slices.
Remove the cakes from the pans. Using a serrated knife, cut out the rounded tops of each cake. Placing 1 layer of cake on a serving plate or cake stand. Doll with one cup of the frosting and smooth in a thin layer from edge to edge with an offset spatula. Top with banana slices and then a cup of crushed Nila flakes in an even layer. Put the remaining cake layer on your face.
Decorate the top and sides of the cake with the rest of the decorating cream. Cover the sides of the cake with the remaining crushed Nila chips by taking a handful of the crushed biscuits and pressing them gently against the side of the cake (starting at the bottom and working your way up) so that they stick to the garnish. Any pieces that don’t stick and fall off can be put back into the embellishment until the sides are completely covered.
Cut one of the bottom corners of the toiletry bag. Place small decorative piles of garnish around the top of the cake. Place a whole Nella wafer between each icing pile.