Easy 6 Layer Rainbow Cake with Vanilla Buttercream

Rainbow cakes is suitable to be served at birthday party because colourful and tasting great. This cake also relatively easy but requires some serious time investment. Here’s the recipe for this one :

Cake : (You will need 3x these ingredients for 6 layers)
          -  170g butter, softened, plus extra for greasing
          -  170g caster sugar
          -  3 large eggs
          -  190g plain flour
          -  1tsp baking powder
          -  45g ground almonds
          -  35ml milk (approximately)
          -  Zest of 1 lemom
          -  1 ½ tsp vanilla flavouring

Food colouring: Red, Yellow, Green, Blue, Purple, Pink          

Frosting :
-  340g room temperature unsalted butter
-  500g unflavored vegetable shortening (TREX)
-  3 tsp vanilla extract (clear if you can get it)
-  3 tbsp milk
-  1.4kg icing sugar (yes that is a lot!)
-  Sugarflair icing whitener
-  Food colouring  for writing (I went for pink)

1. Making the cakes.
Preheat the oven to 180 degrees Celsius. Grease and line two 20cm springform cake tins.
In a large bowl cream together the butter and sugar until light and fluffy. Add the eggs one at time, adding a spoonful of flour if it starts to split. Add the milk, lemon zest and vanilla and mix well.
In a separate bowl sieve together the flour and baking powder. Add the ground almonds then add these dry ingredients to the rest of the cake mix. The cake batter will be thick but should be able to drop from a wooden spoon. Working quickly, separate the mix into 2 bowls (I weighed my batter then halved by weight but if you’re feeling confident do it by eye) and colour. Be brave with your colours, the colour you have in the bowl is going to pretty much be the baked outcome. Bake in the prepared tins for 15-18mins or until a skewer comes out clean. Repeat this method twice more using 4 new colours and leave all layers to cool completely.

2. Frosting.
In a bowl, using an electric mixer, cream together butter, vegetable fat, lemon zest and vanilla until well combined and smooth. Mix in the milk then add the icing sugar in small amounts to avoid an icing sugar explosion. Keep beating until its smooth then add the icing whitener, if using, a teaspoon at a time until white enough.

3. Construction (part I)
Once all the layers are cool, start with levelling your cakes. You want the tops to be as flat as possible here. I needed my cake to be 12cm tall to be able to fit in the only box I had so I levelled all mine to 1cm thick. You want all your layers to be roughly the same thickness. Then, starting with the colour you want at the bottom, spread a thin even layer of buttercream across the top, letting it spill over the edges a little. Place your second layer on top and repeat until all layers are on. Then plop a big dollop of icing on top, and using a spatula evenly spread over the surface and go down the sides of the cake. Try and keep your cake as flat and even as possible. At this stage we are doing a crumb coat so it doesn’t matter if crumbs are in the sides. Put this in the fridge for at least an hour.

4. Construction (part II)
Take your cake with crumb coat from the fridge and start icing your cake. I found it easiest to start with a big dollop on top, spread across and over the sides then spin the cake and keep your spatula level to make even edges. Once you have a good clean layer on, pop it back in the fridge for 30mins. Take it out and decorate with any piping you want to.  I went for simple piped borders and a simple pink writing.


The recipe and image were copied directly from ellenarae