Tokyo Banana Caramel Cake Recipe (Rustic Cake)

March 08, 2016

I've made a Tokyo Banana Roll Cake previously and I'm back with a Tokyo Banana Caramel Cake that consists of Japanese vanilla sponge, filled with fresh banana custard, and coated with home-made caramel swiss meringue buttercream. 

While the normal Tokyo Banana is most commonly known, there are actually many variations of this popular Japanese omiyage (gift). You might have come across Tokyo Banana with different animal prints, giraffe and stripes etc. The one with stripes are actually caramel flavour... and that was my inspiration for this cake!

The flavour itself is so fresh and outstanding that I decided to go for an understated rustic naked-cake look adorned with small flowers (that was washed and pat dry). The cake gives an illusion of having super thick frosting between the layers, but not to worry, the frosting isn't actually that thick! I was inspired by this method to achieve the thick "frosting" layers where there is actually a smaller layer of cake in between the larger layers. 

I baked this cake for my grandmother's birthday, and everyone at the party loved it. Feedback was that the sweetness level's just nice, and the flavour is great! Even though there is caramel in the buttercream, it isn't overwhelmingly sweet as the centre is mainly filled with banana custard (made from ripe bananas). 

Making the caramel from scratch was a fun and easy process. Amazing how just sugar, water and some heavy cream can make caramel. When it was done, the kitchen was filled with a candied aroma - always a promise of something good to come! 

Hope you like my first ever rustic cake recipe! This is a flavour that will appeal to a large audience - regardless of young or old, male or female - great for celebrations and gatherings. Can't wait to come up with new cake creations!

by Sumopocky

2 x 6 or 7" inch round baking pans
Makes 4-layer cake

[For Sponge Cake]
6 eggs (room temperature)
240g of Caster sugar
18g of Condensed milk
210g of Cake flour
60g of Melted butter
60ml of Milk

[For Cake syrup]
100ml of Hot water
80g of Caster sugar

[For Banana Custard]
4 egg yolks
400ml of Fresh Milk
140g of Caster sugar
30g of Cake flour/Top flour
4 ripened bananas (the riper, the better! adjust quantity according to your taste)

[For Caramel Swiss Meringue Buttercream]
Caramel: 29ml of Water
+ 56g of Caster sugar
+ 40g of Heavy cream
120g of Caster sugar
3 Egg whites
225g of unsalted butter (softened)
3 tbsp of Milk

[For Sponge Cake]
1. Preheat the oven to 180°C (356°F). Then, in a metal/heatable bowl, beat the eggs, sugar, and condensed milk over a pot of simmering water until the sugar has completed dissolved.
2. Remove the bowl from heat and use an electric mixer. Beat till the mixture becomes whitish and foamy.
3. Sieve in the cake flour and fold in with a spatula.
4. Pour in the melted butter and milk, and fold till combined.
5. Line two round baking pans with parchment paper and distribute the batter evenly. Bake in the preheated oven for around 30 minutes. Once baked, remove from oven and tap against the table a few times to prevent shrinking. Let it cool before frosting. In my case, I used 7" and 6" baking pans because I wanted to give the illusion that my cake is filled with lots of cream. (steps to do this will be given later). However, if you are going for a normal naked cake, then you can use baking pans of the same size.

[For Syrup]
1. Mix the sugar in hot water until everything has dissolved. Set aside for use later. 

[For Banana Custard]
1. In a large bowl, mash the bananas with a whisk or fork.
2. Add half the portion of milk and the egg yolks. Mix well.
3. Stir in the caster sugar, followed by flour.
4. In a pot, bring the remaining portion of milk to a simmer.
5. Pour the heated milk to the mixture in a steady stream while mixing continuously.
6. Strain the mixture through a sieve. Mash the banana lumps through the sieve.
7. Transfer it to a pot on low heat. Mix continuously until the custard thickens. The right consistency is when you can draw an "infinite" sign with the custard. Remove from heat and cover with a cling wrap (make sure cling wrap is touching the surface of custard) or transfer to a piping bag. Chill it in the fridge.

[For Caramel Swiss Meringue Buttercream]
1. To make caramel, pour water and sugar into a pot. Cook over medium-high heat, stirring occasionally until the sugar dissolves and syrup is clear.
2. Continue to cook until syrup comes to a boil (without stirring). To prevent crystals from forming, wash down the sides of pot with a wet pastry brush.
3. When the syrup boils, gently swirl the pan occasionally to prevent it from burning. Continue until the syrup becomes brown.
4. Immediately remove from heat and carefully pour in the heavy cream. Be care because the caramel will bubble vigorously. Stir caramel until smooth. Let it cool.
5. To make the swiss meringue buttercream, place sugar and egg whites in a metal bowl over a saucepan of simmering water. Whisk continuously until the sugar is dissolved. It is natural for the egg mixture to become thick and sticky.
6. Beat the egg white mixture using an electric mixer with a whip attachment on medium-high speed until stiff peaks form.
7. Continue beating at medium-high speed while adding small chunks of softened butter gradually. It might curdle, but keep beating until the butter is blended in and the buttercream is smooth.
8. Finally, pour in the caramel. If it has hardened, heat over small fire to return it to liquid form again. Mix well and transfer to a piping bag.

[Putting it together]
1. Slice each cake layer into two. Level the cake layers if needed.
2. Spread a bit of buttercream on a cake base to prevent the cake from slipping. If you have baked it in cake pans of 2 different sizes, place the 7" layer as the base.
3. Spread the top of the layer with sugar syrup. Then, pipe out a generous ring of caramel buttercream along the circumference of the cake. Add the banana custard to the center, and stack with the 6" cake layer. Outline the smaller layer with a ring of caramel buttercream. This is what will give the cake an appearance for very thick frosting, when it actuality, it's a hidden layer of cake.
4. Repeat step 3 for the remaining layers and let the buttercream firm up in the fridge slightly.
5. Then, frost the top layer with buttercream. Scrape off any excess buttercream on the sides. Since this is a naked cake, you don't need to be too neat with it. Decorate as you wish! I decorated mine with washed flowers. P.S. This cake is best served when chilled.

Tokyo Banana Caramel Cake

Tokyo Banana Caramel Cake

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