Rainbow Cake!!!!!!!!

I was asked to make a cake for someone that had 6 layers of the rainbow and was decorated with rainbow colours and sweeties on top.  I love a challenge and particularly got excited about this cake as it was something I had experimented with colours-wise when I did my Wizard of Oz cupcakes, but never to this scale.  Check out how this monster of a psychedelic sensation became…

I found that a good way to approach this cake was by reading up on other blogs beforehand.  I generally found that in the UK very few had tried it or had written about it (perhaps due to the lack of getting gel colours until as of late?!) However Kerry Cooks blog was a fab example and helped me get under way.  She decorated hers differently but her cake base was the same as I used.


Cakes (makes all 6)

  • 350g self raising flour
  • 350g Stork
  • 350g caster sugar
  • 6 free range eggs
  • 1 tablespoon vanilla extract
  • about 40ml semi-skimmed milk

Frosting (Fills and makes colours to pipe)

  • 100g butter, soft
  • 250g cream cheese
  • 600g icing sugar, sifted


  • Preheat the oven to 180 degrees and put your oven shelf on the middle rung
  • Grease ad line 3 sandwich tins – I did this in 2 stages as I only had 3 tins, if you have more then that’s great but I sill suggest only baking 3 at a time to achieve maximum fluffiness and minimal stress rotating and changing cakes around on the shelves.
  • Beat together your Stork and sugar until light and fluffy in a food processor
  • Put all your eggs in to a jug and whisk with the 40ml of milk and the vanilla essence.
  • Sieve your flour and set aside.
  • Now with the mixer on low alternate between the egg mixture and the flour – this prevents the mixture curdling.
  • Turn off the machine and divide the mixture between  bowls – I even weighed the bowls – sad I know but I wanted the layers to be as even as possible!
  • Add your colour gels to each of the bowls – as mentioned in previous posts I use the Home2Bake range and they have lasted me for ages, they need to be kept in the fridge to be preserved but other than that they’re the best level of vibrancy I’ve found without buying Sugarflair or Americolor.
  • I chose to make red, orange, yellow, green, blue and purple.  I only have red, yellow, green and blue but found it easy enough to create a bright orange and deep purple by combining these gel colours through the mixture (This also means you an control how bright you make your shades).
  • Pour the mixture in to the tins, bang them on the side a few times to get flat tops and bake for between 15-20mins depending on your oven – when the cake springs back it’s ready!
  • Carefully remove from the tins and place on a cooling rack whilst you reline the tins and reuse them for the other 3 shades.

Cooling colours

  • Once everything has cooled you can start the layering process.  I did this on a separate cake turn table, but if you don’t have one of these just use a normal plate or a plate on a lazy susan. My fiancé’s mum bought me the cake turn table and it’s been a total lifesaver for making big cakes well worth the investment if you can!!!  Make sure you get our colours in the right order though…i started with purple at the base and worked upwards!

Sandwiched with cream cheese frosting

  • Once it is fully stacked use a palette knife to go around the outside…be careful though…

Eeeek getting a lean on here!!

  • Once you are at this stage I suggest putting the cake somewhere cold…it will highly likely be too tall for your fridge so the garage of somewhere similar with a food cover should do the trick.  I’ve found that up here in the North, my porch provides rather chilling temperatures and does the trick just as well!
  • Now is the time to transfer to your cake board…but be careful this is a precariously tall skyscraper of a cake right now – fish slices and minimal distance to transfer is the key!!!
  • Now you are ready to start layering the outer colours…
  • I used disposable bags for this and divided up the remaining cream cheese frosting in to 5 bowls adding red, orange, yellow, green and blue gel to each batch.
  • I started with red and then worked out how far up the cake the next colour would go…don’t worry if it’s a bit wonky or messy because a palette knife will rescue this shortly!

Piped on stages of colours

  • Yes it looks messy but we can fix that!  Beware…cream cheese is not as ‘firm’ as butter cream so this will be tricky and a bit stressful but the outcome will be worth it.  A flat-ish nozzle proves most effective in sticking to the under layer of cream cheese.
  • Now holding the palette knife up straight smooth around the cake and wipe the excess off…some colours will mix but that’s the beauty of the outcome!

Smooth with a palette knife

  • Now yo’re ready for decoration and prettiness.  I used a small bit of the red and blue cream cheese I had left to pipe a purple star like pattern around the top.
  • I then use Haribo sweets to cover the top in a pattern and put aside the teddy bears.

Haribo display of hearts, eggs, teddies, cola bottles and rings…

  • The teddies then sat around the base…

Topped with Haribo goodness and sleepy teds around the base!

Now it’s finished and ready to be devoured.  Leaving the cream cheese to ‘set’ for a while would be best and again a cool place is recommended.

Finished product

Full internal cake view!

I didn’t actually know what the inside would look like until I was messaged the next day from my mate but the colours came out super well and incredibly vibrant.  The biggest satisfaction was seeing the birthday girl’s face…cake and all…

One very happy cake customer!

Give it a go!  It’s a long process and you won’t know the outcome until it’s cut in to but it’s very satisfying and what cake doesn’t make people grin when they can see the colours of the rainbow and enough Haribo’s to sink a ship?!

Zoe :)

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