Charity Shop Vintage Finds, Granny Chic, Sewing and Baking with Giddy Aunt Lola

Tuesday, 4 June 2013

Rainbow Birthday Cake

Rainbow Birthday Cake

My Curly Girly had her 6th birthday party last Saturday and on the morning of her party she helped me make the Rainbow Birthday Cake.  I have never met a child who didn't like baking; they love the weighing and mixing and more than anything, they seem to like cracking eggs!  She spotted the cake in The Clandestine Cake Club Book and set her heart on it.  My first reaction was that it looked like it would be too much of a faff to get done on the morning of her birthday party, but au contraire, it was a doddle.  

The key to success with this cake is to use gel food colouring; we used these Wilton Icing Colours and they worked like a dream.  You only need a tiny amount on the end of a cocktail stick to get the above results.  Yes, they do have quite a few E numbers, but as you only need a weeny bit and it was for a birthday cake, I think we could justify a few E's.  Don't be tempted to use liquid food colouring as it just won't work; it makes the batter too wet.

The cake is basically a big batch of sponge mix that is then split between five small bowls and different colours added to it.  As I only have 2 cake tins, I had to bake in batches, but this wasn't really an issue, as the cakes only needed around 15-20 minutes to cook. 

As you can see, the sponges look a little subdued when they came out of the oven and it wasn't until the last glorious moment, when we had sung happy birthday and cut into the cake, that a bright zinging rainbow was revealed!  It was a 'YES!' moment and a great ending to a fab party.  

The party itself was a big success and Disco Dad set up his bar for Mocktails and Tizer floats.  The girls  sat on bar stools and sang along to Taylor Swift and One Direction after getting glammed up with a shed load of glittery nail varnish and purple spray-in hair colour.  Claire's Accessories are brilliant for cheap and cheerful nail varnishes (£1 each).  

The Recipe

Here is the recipe that I have adapted from the Clandestine Cake Club book.  By the way, this book is brilliant and I'll blog more about The Clandestine Cake Club soon.  


350 grams Stork margarine (or butter if you prefer)
350 grams Caster Sugar
6 eggs (mine were medium to large in size, as that's what my chickens lay)
350 grams Self-Raising Flour
5 different gel food colourings
1 tsp Vanilla extract
Decorations (I used little sugar flowers)

Buttercream Filling and Topping

250 grams Stork margarine (or butter of course)
1 kg Icing Sugar
2-3 tbsp milk


  1. Pre-heat oven to 190 C and line how ever many round cake tins you have - I had 2 x 20 cm tins, but you could use 18 cm tins and have a taller cake!
  2. Beat the margarine and sugar together with an electric whisk or with a wooden spoon if you have big beefy biceps.  
  3. Add the eggs one at a time (picking out the bits of shell after your 6 year old has been a bit heavy handed with the cracking!) and whisk slowly.
  4. Add the vanilla extract and sift in the flour; mix on a low speed until combined.  
  5. Divide the mixture between five small bowls and add a different colour to each bowl.  Do not let your 6 year old dip their finger or tongue in the gel!  Remember you only need a tiny amount on the end of a cocktail stick.  
  6. Transfer each coloured mix to a baking tin, spreading it out evenly and bake for 12 - 15 minutes.  You will have to adjust times according to your oven.  Leave cakes to cool and let your 6 year old lick the whisk to keep her quiet.
  7. To make the buttercream, beat the margarine with the icing sugar, on a slow speed.  My top tip is to cover your food mixer with a tea towel, to avoid the clouds of icing sugar that will cover your kitchen otherwise!  Add as much of the milk as you think you will need to make a good spreading consistency (too sloppy and your cakes will slip off each other; too thick and it is difficult to spread).  
  8. Now to assemble your rainbow.  Put your first sponge on a nice plate and spread the top with some of the filling.  Add your second sponge and keep going like this, sandwiching your cakes with buttercream until you have a towering rainbow.  I gave my cake a firm pressing down before covering the sides and top with the remaining buttercream.  I didn't colour my buttercream but if you want to go psychedelic, then go for it.   
  9. Decorate in any which way you so desire.

Cut your cake and enjoy the 'YES!' moment.  

Giddy Aunt Lola x 



  1. Fabulous GAL! Well done you. I'm almost tempted to try this sugar rainbow creation myself....damn this diet!!! :-(

    1. Hello Little Witch, get busy with the E numbers; I am absolutely certain that eating rainbows is good for you


Hi, thanks for taking the time to comment. GAL x

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