Five layer rainbow cake
So, it was that time of year again. Birthday time.
You may not know this but I am incredibly organised – okay, you could say I’m a control freak – and both my children share the same birthday a year apart.
And when the new school year starts, I start frantically trying to plan a birthday party for them.
This year was no exception apart from Ruby’s request – quickly joined by Isabelle – that they couldn’t wait to see their cake and *I’ll have to whisper this because it’s like blasphemy* could they BUY a lovely one from Costco.
Yes, my children, ladies and gentlemen – the cake philistines!
Not one to disappoint I duly trotted off to said shop and went to order said cake. But its bakery was having a refurb that very week and no baking would be taking place. I was secretly seething at this point as I’d not planned a cake and didn’t know what to do.
But then the cake fairy appeared – in the form of The Pink Whisk – and the concept of a rainbow cake was born!
It was a lovely cake, really easy to make – apart from the fact I only had one tin, so had to bake the five sponges individually.
I doubled the quantities below as my tin was huge and I had at least 30 kids plus adults to feed. I would say the double mixture would happily feed 50 – and it was a big slice of cake too, incorporating one of each colour layer.
500g butter. Now I used Aldi’s baking butter at 49p for 250g and it was a steal and worked really well. I checked the fat content and it was in 70% range, so I would thoroughly recommend it.
500g flour. I used plain and then added salt and baking powder. You will need 1/2tsp of salt and 1.5tsp of baking powder per 500g.
1tsp vanilla essence. Yes, essence, I always use it and never its more expensive cousin extract.
Gel paste colourings. These are a must. Buy them in five rainbow colours of your choice. I chose Christmas red, Tangerine orange, Egg yellow, Holly green and Ice blue – as I knew I would use these colours over and over again in other things. Gel pastes last for eons as you only need a small amount.
Heat the oven to 160 (electric fan) and line a tin/ tins (if you happen to have five!) with greaseproof paper. I think this quantity will give you five decent sponges for an 8inch round or heart tin. As I said I had a 10inch square tin and doubled the quantities.
I also got out five bowls so that I could divide the mixture once it was made.
Make sure your butter is room temperature and softened. I use a freestanding mixer and would definitely recommend it if planning to make the double amount. There is no way a handheld could cope with it.
Place butter and sugar in the mixing bowl and beat with a paddle attachment for at least five minutes until it is light, fluffy and completely combined together.
While this is beating, put flour, salt and baking powder in a bowl and mix together.
Once the butter and sugar mixture has been beaten, add in the vanilla. Scrape down and add in the eggs. One at a time and always follow each one with a tbsp of flour. It stops the mixture splitting.
Once all the eggs have been incorporated, add in the rest of the flour, a ladleful at a time and scrape down the bowl, giving it one final mix.
Next, get your weighing scales out and place in front of your five bowls.
To make the sponges the same thickness, you’ll have to weigh the batter. I made it around 400g per sponge, per bowl. Place the amounts in and then get your gel pastes out. Add in enough of the paste until you have your desired colour.
Place in the oven and bake. Around 20-25 minutes per cake. I even found that by doubling the quantities, the cooking time was roughly the same. Needless to say if you are doubling up, your weight per sponge will be around 800g.
If I could give you one tip that would be to cook the blue and the green sponges first. Basically your bottom sponges and bake upwards. As they cool you can then assemble from the base upwards and you won’t be wasting precious time waiting for them all to cool before the icing stage! I learnt the hard way!
Once cooled, you’re ready to ice and assemble.
I decided on a plain vanilla buttercream, with pink fondant butterflies and some little pink buttercream icing stars piped around the bottom, where the cake meets the board to hide any blemishes) and around the top of the cake, just to break up the white buttercream.
I tried to use an icing scraper to create pattern around the side but -more practice needed, I think.
I needed 1.5x the mixture below for inside the sponges and the crumb coat. I then needed another quantity to cover the cake for the final layer.
Ingredients – Buttercream
160g softened butter – proper, unsalted butter this time please.
500g icing sugar
2tsp vanilla essence
Around 60ml of milk, a little more, a little less – depending on consistency, your room temperature that day.
Put butter and vanilla in the mixer with the vanilla essence and beat to break up the butter. Add in the icing sugar a little at time – unless you want your kitchen covered in fine layer of dust! And once all in, beat until you get a sandy consistency.
Slowly add in the milk until you get the consistency you want. For spreading and covering, I like it a little less stiff than if I was piping onto a cupcake.
Beat for around 10 minutes until light and fluffy. You’ll also get more out of your buttercream this way as it does increase in volume.
Then layer up the sponges, buttercream and raspberry jam between in each layer and cover all the sponges in a crumb coat and place in the fridge for 30 minutes to set.
Make up another batch of buttercream and cover the cake in its final layer. Decorate as you wish!
Layered up ....
My green sponge went a little funny and I have no idea why. It didn’t seem to rise as much as the others and seemed a little dense. Just luck of the draw but less cakey people never even realised – phew!
Crumb coat on
And finally … the big reveal …
Inside of the rainbow cake