7-layer Rainbow Cake (and other Rainbow Cakes)

Apologies for the month-long hiatus – I have been baking (evident if you have been following my Instagram), but just did not get around doing the blog posts on them.

This post is about the first commision cake I’ve ever baked, so I was a little nervous about it. I can’t just bin the cake if it doesn’t come out the way I wanted it to. A colleague at work requested a few weeks ago that I bake a cake for her sister’s birthday. She wanted a rainbow-layered cake for the wow factor but not too immature a design, and her sister likes chocolate and the colour purple.

Now, I have actually baked a rainbow cake before, but it wasn’t a layered cake. It was an almond-flavoured psychedelic rainbow cake, and it looked kinda insane. It was for another colleague’s last day at work and I baked it at 11pm the night before.

I covered it in white chocolate ganache so it looked like an unassuming, homebaked white cake. Novice baker than I was (and still am, really), I worked with a spoon to spread the ganache. And when you sliced it open, it revealed the crazy pattern inside.

Original Rainbow 'Nyan' Cake
Original Rainbow ‘Nyan’ Cake

I even did a cupcake version of that for the same ex-colleague’s housewarming party.

Rainbow cupcakes! With my poor icing skills! XD
Rainbow cupcakes! With my poor icing skills! XD

However, that’s not what the latest cake is about. The latest cake is an 8-inch 7-layer vanilla white cake, with each layer a different colour, covered in white chocolate buttercream and encircled with two-toned purple-and-white piped roses, with piped lettering on top. I’ve not done piping much before, and certainly never attempted to pipe lettering, and my handwriting is pretty shocking. Why did I agree to piping anything?!

Anyway, not a lot that can be done about it, so on Saturday, I went to work. I used the white cake recipe from Woodland Bakery Blog to start with. I really like how she has included the weight of each ingredient rather than just measuring volume. Once the batter was made, I divided the batter by weighing into seven different bowls and colouring them with gel or powder food colouring. This is where I started to run out of bowls to work with.

Seven bowls of cake batter, seven colours. Deja vu!
Seven bowls of cake batter, seven colours. Deja vu!

The problem with dividing cake batter for one cake into seven different portions and baking them seperately is that there isn’t really that much batter in the baking tin when you bake each layer, so you really have to scrape the bowl clean and try your best to spread it out in the tin.

Then I had to work out the baking time for each layer, because suddenly, the recipe’s time won’t work. With a tiny bit of experimentation, my oven took 12 minutes for each layer to be fully baked without being dried out or burnt.

Flying by the seat of my pants here, people.

Also had to clean the tin out and reline it every time I took it out of the oven to bake the next layer. I mean, I didn’t think any home baker would have seven of the same sized cake tin in their house unless they’re a bit special.

A couple of hours later, all the flat surfaces in my kitchen were covered in plates bearing one of the layers, cooled and awaiting assembly. Whilst I was waiting, I got started on the buttercream, which was made of 550g unsalted butter, 550g icing sugar and 200g melted white chocolate whipped into a smooth, creamy consistency.

Crumb coat. You can see the colours peeking through!
Crumb coat. You can see the colours peeking through!

You can sort of see the different colours through the crumb coat. Due to the different layers and the layers of buttercream sandwiched in between, it ended up being a pretty tall cake.

Once the crumb coat had some time to dry out slightly, I divided the rest of the buttercream and coloured some of the with Wilton Grape/Violet gel colouring and got to work with piping the lettering and the roses. The lettering is done with number 3 plain tip and the roses are done with 1M tip.

Buttercream rose swirls on the side and my first attempt at piping words!
Buttercream rose swirls on the side and my first shaky attempt at piping words!

I almost ran out of buttercream and almost did not manage to finish the roses! That would have been a disaster! Luckily enough, I managed to squeeze the piping bag to the very last bit to finish it up. For future reference, I probably should make more buttercream if I am going to be doing more than 2 or 3 layers.

The worst part about doing a commission bake is that a) I can’t taste test it; and b) I can’t cut it open and see what it looks like! I have to go by faith that it will be fine and it will taste fine. My colleague was kind enough to post a picture of the cake being cut, which looked better than I thought it would turn out to be.

Inside the 7-layered Rainbow Cake!
Inside the 7-layered Rainbow Cake!

I’m not sure I would do another 7-layered cake though – it was pretty time-consuming with a lot of washing up required in between and afterwards, and I already hate washing up as it is.

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