The Rainbow Cake

So many people have been asking me for the recipe for Elisha's birthday cake, so I thought I'd post it here for y'all.

I'd love to be one of those beautiful blogs that has step by step photo instructions for each step, but that would take a ridiculously long time, so you'll just have to put up with the few photos I have.

Step one - Making a rainbow cake mix

The first step is a basic white cake recipe, doubled, with whatever flavouring you want to add. I've used lime. You will need:

  • 2 cup white sugar
  • 1 cup butter
  • 4 eggs
  • 4 teaspoons lime juice
  • 3 cups all-purpose flour
  • 3.5 teaspoons baking powder
  • 1 cup milk
  • Red, Yellow and Blue food colour gels (very important)

  1. Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x9 inch pan or line a muffin pan with paper liners.
  2. In a medium bowl, cream together the sugar and butter. Beat in the eggs, one at a time, then stir in the lime. Combine flour and baking powder, add to the creamed mixture and mix well. Finally stir in the milk until batter is smooth.
  3. Split the batter evenly into six bowls.
  4. Colour each bowl with gels and stir well (red+yellow = orange, red+blue = purple, blue+yellow = green)
  5. Pour batter into grease and lined cake pans and bake at 190C until just starting to brown. Watch them, because they will go very quickly as they are thinner
  6. than your average cake
  7. Set aside to cool

Here I'd like to add a quick word about gel food colour. It is definitely worth the investment. The colours are so vibrant. You couldn't get the same effect with food colouring unless you used tons, which would alter the consistency of your batter and also make your cake taste horrible (whilst
filling your little ones up with E-numbers). Food gels require a tooth pick full
in each bowl for these quantities and will give you a lovely strong colour, without affecting the liquid content or flavour of your batter.

You should also make sure you bake the cakes in colour order if you only have one pan/spatula (like me). That way, if there is any batter left from the previous cake it sort of blends ;0)

Step Two - Filling and crumb coating
    1. For this step you need to make a kind of meringue mixture. Start off by putting 3 cups of sugar and a half cup of water in a pan. Place it over a low heat and swirl it until you have a lovely sugar syrup with no crystals left in it.
Do not let it brown or it will colour your frosting.

Once your sugar syrup is ready, quickly whip up four egg whites in your kitchen aid (or other electric whisk) and then leave it whipping at a high speed as you gradually drizzle in the hot syrup.

It is very important that you add the hot syrup slowly whilst the m
    1. ixer is on a high speed. The egg whites are going to be cooked by the sugar, but if they aren't being whipped at the same time you will end up with a heavy lump instead of light fluffy frosting.

Once it's all added leave the mixer running for 10-15 minutes or until the frosting is completely cool. This is very important too. As the sugar cools, it solidifies, and we want it to by solid with lots of tiny air bubbles in it, not a hard lump at the bottom of the bowl.

Scared? Don't be. It's really very easy.

Once it's done, layer up your cakes in colour order with plenty of frosting in between each layer and crumb coat
it. Now place it in the freezer whilst you move on to...

Step Three - Decorating

This step requires some more of the frosting from step two, you should have some left, but if you don't, quickly whip up another batch.

Change the whip attachment on your kitchen aid for the paddle/beater and slowly add butter (100g) and the juice of one lime. You frosting will go soupy, that's fine, just keep beating it and adding a little confectioners sugar until it becomes useable again.

Bring your cake out of the freezer (it should be hard and super easy to frost now without crumbs going everywhere) and cover it beautifully.

Sprinkle with rainbow dust, grate lime zest on and add candied limes around the sides. Cut up some dragonfruit and arrange it in a star on the top of the cake. I have to say I was slightly disappointed with the colour of my dragonfruit. I expected it to look like this:
But unfortunately I seem to have bought a white one, so I jazzed it up with some strawberries. Add a candle and you're done!


  1. It looks amazing Katie. May have to try it and eat it all by myself!

  2. Hey! I have seen this post floating around pinterest! Its nice to have found the original :)


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