Mosaic Rainbow First Birthday Cake -- Milo & Horlicks Chiffon with Chocolate Swiss Meringue Buttercream

Here's a colourful First birthday cake as my first post for a new year of creative bakes!

This is a four-layered Milo and Horlicks chiffon cake with extremely chocolatey Swiss meringue buttercream and vanilla chiffon cake as rainbow decorations. Most first birthday cakes are either polka dot or stripe themed so I thought why not make something more unique!

Vanilla layer cakes (for rainbow colours, makes two 9x12" flat layers or any pan of similar size)
Ingredients:
3 egg yolks
15g caster sugar
45g vegetable/ canola oil
45g water
1/3 tsp vanilla extract
Pinch of salt
60g cake flour
Gel food colouring

4 egg whites
1/4 tsp cream of tartar
40g caster sugar

Steps:
1. Line the trays and preheat the oven to 160°C.

2.  Prepare the egg yolk batter. Whisk egg yolks and sugar until pale and thick. Take a few minutes to do this. Gradually add oil and whisk until consistency is like mayonnaise. Gradually add water and vanilla extract while whisking until well combined. Gradually add in sifted flour and salt and whisk until no trace of flour is seen. Divide the batter into 6 portions and add food colouring according to the colours of the rainbow.

3. Prepare the meringue. In a clean metal bowl, beat egg whites until foamy with electric mixer. Add cream of tartar and beat until soft peaks form. Gradually add sugar and beat until stiff peaks form. You should be able to overturn the bowl without the meringue falling out.

4. Fold the meringue into all the different coloured egg yolk batters in three additions. Pour three coloured batters into each pan, side by side each other.

5. Bake for 11-12 minutes or until skewer comes out clean. Immediately remove cakes from pan and gently peel off baking sheet. Cool with a fresh baking sheet over the cakes. Store the cakes in a large ziplock bag or airtight container until it is time for assembly.

Chocolate swiss meringue buttercream (smbc, adapted from Baking Library)
Ingredients:
100g egg whites (3-4 eggs)
68g caster sugar
180 unsalted butter, cut to tablespoon-sized pieces, softened but cool
1/8 tsp salt
35-50g cocoa powder (Adjust according to how chocolatey you want. I used 50g as my requester wanted it to be very chocolatey.)

Steps:
1. Heat a saucepan of water (water about 1" deep) and set to simmer. Place egg whites, sugar and salt in a big metal bowl that can be placed over the saucepan. Whisk the egg whites with the bowl over simmering water without letting the bottom of the bowl touch the water. Keep whisking until warm to touch and all sugar has dissolved. This takes about 6 minutes. If you have a thermometer, keep whisking until temperature is 71°C.

2. Take the bowl off the heat and use the electric mixer to beat on high speed until meringue is stiff, glossy and cool to touch. This takes about 10 minutes.

3. Add the butter one piece at a time, beating at low speed. Make sure the butter is well incorporated before adding more. Don't worry if it curdles. Just keep beating and adding more butter gradually. Beat on medium high speed until fluffy when all butter has been added. About a couple of minutes.

4. Gradually add in sifted cocoa powder and beat until well combined.

You may make this in advance and freeze for up to a month or refrigerate for up to a week in ziplock bag. Just bring the smbc to room temperature and whip it again before using.

Horlicks/ Milo chiffon layers (makes two 9"x12" layers. I made 2 of each flavour. Adapted from my Milo log cake.)
Ingredients:
6 egg yolks
24g caster sugar
84g vegetable oil
84g hot water
66g Milo or Horlicks
75g cake flour
1/4 tsp salt
1.5 tsp vanilla extract
Blue gel food colouring (for Horlicks layer)

8 egg whites
1/2 tsp cream of tartar
88g caster sugar

Steps:
1. Dissolve Milo/ Horlicks in hot water. Set aside to cool.

2. Follow steps 1-4 for vanilla chiffon layers, except that you bake at 165°C for 14-15 minutes or until skewer comes out clean. Divide the egg yolk batter and meringue ingredients into two if your oven can't fit 2 trays at once. You may wish to apply some oil on the baking sheet for the horlicks layer that is showing to prevent it from sticking to the baking sheet.

Freshly baked Horlicks cake!

Assembly
1. Use a small triangle cutter to cut out about 50 triangles for each of the rainbow colours and keep in airtight container or cling wrapped bowls.

2. Make a "1" template and cut out 2 layers of Milo and 2 layers of Horlicks layer cakes using a sharp serrated knife.

3. Alternate layers of cake and re-whipped chocolate smbc. I find it helpful to pipe on the cream but you may apply using spatula.

4. Carefully apply some cream at the sides of the cake. Add on the name. You may stick the name on using smbc or melted marshmellow. If using smbc, be careful not to let the cream show.

5. Stick on the triangles with the same colours staggered in different rows. Brush the surface of the cake, especially the small pieces of stick-ons with simple syrup (1:1 ratio sugar:water) to prevent the cake from drying out.

6. Keep the cake in a cake box in the fridge. Let it sit at room temperature for a while before serving if you prefer softer buttercream.

Finally done!

Unfortunately, there was some miscommunication and the requester actually planned for a polka dot themed party! I had to redo the cake deco and tried my best with whatever cake that was left, and came up with this...

The cake is really soft and moist, overall very chocolatey and well received by the guests! I would personally prefer fresh cream to chocolate smbc for this Milo and Horlicks chiffon sponge combination to let the cake flavours shine through.

With love,
Phay Shing