This Banana Pudding Cake combines all of the elements of the classic southern dessert. Vanilla cake, banana pudding, and vanilla wafers with vanilla buttercream and fresh whipped cream.
Preheat oven to 350F. Grease and flour three 8" cake rounds and line with parchment.
In a medium bowl, whisk flour, baking powder,and salt until well combined. Set aside.
Using a stand mixer fitted with a paddle attachment, cream butter and sugar on med-high until pale and fluffy (approx 3mins). Reduce speed and add eggs one at a time fully incorporating after each addition. Add vanilla.
Alternate adding flour mixture and milk, beginning and ending with flour (3 additions of flour and 2 of milk). Fully incorporating after each addition.
Bake for approx. 30 mins or until a toothpick inserted into the center comes out mostly clean.
Place cakes on wire rack to cool for 10 mins then turn out onto wire rack. Allow cakes to cool completely.
Banana Custard (make in advance):
Place 1 1/2 cups milk and vanilla bean paste into a medium saucepan. Cook over high heat, stirring often until it just starts to simmer. Remove from heat.
In a medium bowl, whisk remaining 1/2 cup milk, egg yolks, sugar, and cornstarch.
While whisking vigorously, slowly pour the hot milk into the egg mixture.
Return mixture to saucepan, add banana liqueur and cook over high heat, whisking constantly, until it thickens and comes to a boil.
Pass through a strainer and into a small bowl. Place plastic wrap directly on top of custard to prevent a skin from forming. Cool to room temperature then place in refrigerator a couple hours to set.
Swiss Meringue Buttercream:
Place egg whites and sugar into the bowl of a stand mixer, whisk until combined.*
Place bowl over a pot with 1-2" of simmering water and stir constantly with a whisk until the mixture is hot and no longer grainy to the touch or reads 160F on a candy thermometer (3mins)
Place bowl on your stand mixer and whisk on med-high until the meringue is stiff and cooled (the bowl is no longer warm to the touch (approx. 5-10mins)).
Switch to paddle attachment. Slowly add cubed butter and mix until smooth.** Add vanilla and mix until smooth and fluffy.
Whipped Cream:
Whip cream and sugar until stiff peak (in a cold bowl with a cold whisk for best results). Fill a piping bag fitted with a large star tip (I used a 1M tip).
Assembly:
Place one layer of cake on a cake stand or serving plate. Do a thin coat of buttercream on the layer and pipe a dam around the edge using a large round tip to hold in the custard (I did a double height dam).
Place whole Nilla wafers on the bottom within the dam.*** Top with 3/4 cup banana custard and spread evenly. Top with banana slices. Repeat with next layer.
Place final layer on top of the cake and frost and smooth the outside with a thin crumb coat. Chill for 20mins.
Frost the top and sides of using the remaining buttercream. Smooth the sides and the top and then use a fine toothed cake comb on the sides.
Do rosettes on top with the whipped cream and alternate banana slices and Nilla wafers between them. Spread some crushed Nilla wafers along the bottom if desired.
Notes
* Ensure there is no trace of egg yolks in your whites and that your mixer bowl and whisk is completely grease free or your meringue won't stiffen. ** The buttercream may look like it's curdled at some point. Keep mixing until it is completely smooth. *** Mine fit about 13 Nilla wafers per layer. Alternatively you can put the custard and bananas down first and then top wit chopped Nilla wafers instead.