Rainbow Layer Cake

2015-05-10 13.42.54

Unassuming and simple from the outside, but when it’s cut into it has the most amazing layers of colour. This cake really does have the wow factor!

I’d been wanting to make this cake for a long time but hadn’t found an reason good enough to actually make it. I waited long enough and the perfect occasion came around – Rien’s brother, Daarek’s birthday. I knew this would be the perfect cake for him and I wasn’t wrong! He is always so complimentary with my cakes so I wanted to step it up for him and make him a birthday cake that was a bit special.

2015-05-10 13.44.30

The inspiration for this recipe came from a lovely blog, Kerry Cooks. Her blog was the first place I remember seeing a rainbow layer cake that actually gave you a recipe to make the cake yourself. A lot of the American recipes  use a boxed cake mix. Her blog has some fantastic tips which I was able to use and adapt slightly to create my Rainbow Layer Cake.

You may look at this cake and feel slightly scared, but there is really no need to be! You need to make sure you have the right equipment and then you’ll be fine. To make this cake as easy as possible, I bought the Easy Cake Layer Pan Set by Wilton from Lakeland. I’m sure there are plenty of places you can buy them online. One tip if you do buy these cake pans; do not believe them when they say they are non stick! I stupidly believed that they were the first time I used them to make an ombre cake and ended up with some cake getting stuck to the pans. I recommend lining the tins with baking paper to prevent this from happening. On her blog, Kerry used disposable pans which you can find in lots of supermarkets and pound shops which is a great tip if you don’t want to buy any new equipment.

The cake pan set is for 5 layers, so the recipe below will make you a 5 layered rainbow cake. Each pan is 6 inches which I think is the perfect size for this cake seeing as you are stacking 5 layers of cake with lots of buttercream. It also means each layer isn’t too thick. If I were to make this cake for myself, I would use cream cheese frosting like Kerry did. However most people, including Daarek, prefer buttercream so that is what I used.

2015-05-10 13.42.41

You also need really good gel colouring to get the fantastic vibrant colours. The liquid food colourings you can buy in supermarkets just aren’t good enough. You need concentrated gel colouring which you can buy online or in shops like Lakeland and Hobby Craft. My favourite brand to use is Wilton because they have a great range of colours an can give you really bright colours without having to use loads of it.

When it comes to icing cakes I think it is definitely worth investing in a cake turntable. This allows you to smoothly turn the cake backwards and forwards when you’re decorating it which is a huge help! I also use a large off-set spatula to apply the buttercream to the cake holding it at a 90Ā° angle. A spatula dipped in hot water and then dried is a great way of getting a smooth finish on your cake. There are lots of different techniques and ways people find help them, but this is what works for me.

What I like most about this recipe is this one cake mix will make enough for all 5 layers so you don’t have to faff around making different mixes. An obviously that it looks pretty amazing!

2015-05-10 13.37.23

For the cake 
225g butter or margarine
225g caster sugar
4 large eggs
1 tsp vanilla extract or vanilla bean paste

225g self-raising flour
2 tsp baking powder

  1. Preheat the oven to 180Ā°C/160Ā°C fan. Line you cake pans
  2. Add the butter and sugar to your bowl and cream until light and fluffy. Add the eggs one at a time starting on a low speed and increasing it after each egg has been added. I find this helps incorporate the eggs better. Add the vanilla and mix again before finally adding the flour and baking powder
  3. Split the cake mix equally into 5 different bowls. I do this by weighing my mixer bowl when its empty and then taking this away from the weight when it has the finished cake mix in. I then divide this by 5. You can do it by eye but I prefer to be exact as this will help make even layers
  4. Colour each bowl of cake mix a different colour – I coloured mine red, orange, yellow, green and blue but feel free to use whatever colours you like. Start with a small amount of colouring as a little bit goes a long way. You an always add more and make it brighter but you can’t make it lighter again!

2015-05-09 14.34.04

  1. Pour each bowl of coloured cake mix into your prepared tins and bake in the oven for 10-15 minutes. They’re done when a cocktail stick comes out clean

2015-05-09 14.50.54

  1. Allow the cakes to cool slightly in the pans before turning out onto a wire rack and let them cool completely

2015-05-09 15.45.03

  1. Once completely cooled, level the cakes so that they stack more evenly. I do this with a cake wire which allows you to cut a clean level line using a serrated wire. You can use a knife but I find this works better and reduces the risk of making a mistake! I set the cake wire to the height of the cake that needs the most cut off it to make it level. You’re looking to take the smallest amount of cake off to make the cake flat

2015-05-09 16.56.27

  1. Once the cakes are leveled, you’re ready for the buttercream!

2015-05-09 17.00.05

For the buttercream
420g unsalted butter
840g icing sugar
4 – 6 tbsp milk

  1. Mix the butter and icing sugar together until pale and smooth. Add enough milk until it is a smooth spreadable consistency
  2. Starting with the blue layer, place one layer onto your cake board and then add a generous layer of buttercream. Repeat with all 5 layers

2015-05-09 17.21.28

  1. Once all of the layers are stacked, it is time to apply the crumb coat. This locks all of the crumbs in place so that the final layer of buttercream is smooth and crumb-free. Do this by applying a thin layer of buttercream to cover the whole cake. At this stage it doesn’t have to look pretty. After you’ve applied your crumb coat, but in the fridge for at least 30 minutes for it to set slightly

2015-05-09 18.22.53

  1. Once the crumb coat has become firm to the touch, you can now apply the final layer of buttercream. Make sure you use quite a generous amount of buttercream and take your time!

2015-05-09 18.47.10

  1. You can decorate the cake however you would like. I chose to keep it completely plain on the outside and made some bunting to stick in the top

Make sure you check out Kerry’s blog http://kerrycooks.com/easy-6-layer-rainbow-cake-step-by-step/

Apologies for the photos not being the best, I always find it hard to take photos of cakes I have made for people. And I can’t take my usual kit with me!


15 thoughts on “Rainbow Layer Cake

  1. Sharon

    What a great cake, Cat!!!

    Coincidentally, I was looking at the Wilton pan set in Lakeland Milton Keynes only yesterday afternoon. I was really good though and resisted the impulse purchase, but I think this post is a sign I should buy them šŸ™‚

    2 quick questions for you, if you don’t mind:
    – How tall was the finished cake?
    – How many servings did you get?



    1. Cat Post author

      Thank you šŸ™‚

      That is the exact shop I was in and got drawn into buying it! You should definitely buy them, they make this recipe a lot easier and I don’t think they’re a bad price at all.
      The cake was roughly 7″/18cm tall which was a pain as it was slightly too tall for my cake carrier! This meant transporting it in the car a little nerve wracking!
      Normal sized slices maybe 14ish? We had 8 slices then I think there was just under half the cake left which we left with my boyfriend’s family.

      Thanks for stopping by šŸ™‚ x

  2. Betty

    I made this yesterday!
    I was truthfully really nervous about it since there were no ratings or any reviews, but i think it turned out okay : )
    My pan was like 8 inches or something so the layers were much thinner than yours, more like pancake-width than actual cake layers LOL.
    I was going to do do this frosting recipe: http://iambaker.net/the-perfect-crusting-buttercream/ , but i think i failed that miserably, i don’t have crisco shortening here in australia, so i used butter… But i did follow your buttercream recipe for the outside, and it covered it perfectly! I could have made the colours a little bit more vibrant, but i think it’s fine : )
    One thing i must say for anyone else trying this though; it’s extremely sweet, i had already shortened the caster sugar off and the confectioner’s sugar down a bit, but it was so sweet. I had one slice and i was done for the night; I will make this again, but it does take a long time, since i only have 2 baking pans.
    Overall, the inside looks amazing~ and i think this was a success! <3 Thank you~

    1. Cat Post author

      Hi Betty!

      That looks great! Thanks for sharing your photo!
      Haha, yes unfortunately I’m quite a small blogger so my posts don’t always have comments like the more popular bloggers. I do try to include as much detail and as many photos to show exactly how I have made a recipe which I hope helps.
      Although like you said your layers are slightly thinner, they are still really well defined. I think your colours look great, especially the red and blue šŸ™‚ You could always use make a pastel rainbow cake too!
      Ooh I’ve never even heard of that frosting recipe so I’ll have a look.
      From what I can tell Crisco is the equivalent of something called Trex here in the UK (not that I’ve ever used it). I think (but not completely sure) that is a vegetable version of lard? Which if it is is slightly strange to use in buttercream?
      I agree with it being sweet, but I think that might be because I’m not a fan of buttercream! When I’ve made this cake I’ve had no complaints though šŸ™‚
      Oh wow, I bet it did take a while then! If you do plan on making it again, you could see if anywhere with you sells a similar set of pans like I used here. The one I bought wasn’t very expensive and made it a lot easier and quicker!
      Thank you for stopping by and commenting and I’m glad you liked it šŸ™‚ x

  3. Steph foster

    Hi! I had my first attempt at a rainbow cake today! So the cake part came out great, which I wasn’t expecting (because I had to divide the mixture by sight!) but I made cream cheese frosting and it wasn’t enough, and I was a bit confused about how much you put on the crumb frosting part?! Could you share your cream cheese ingredients?
    The recipe was great for the cake šŸ™‚

    1. Cat Post author

      Hi Steph,

      Really glad the cake turned out well šŸ™‚

      The thick cream cheese recipe is here http://www.curlyscooking.co.uk/?p=1710 which should cover the cake easily. I’ll make sure I link to it in the recipe too šŸ™‚ The crumb coat is a really thin layer which is there to bind the crumbs to the cake so they don’t interfere with the final coat. You will still see the colours of the cake through the crumb coat.
      Hope this helps x

  4. Sheri

    Hi, I made this cake for my sons first birthday today and it gets the thumbs up from us!
    Really easy to follow and a great result. I would attach a pic if I knew how!!

    Thank you, will definitely make again.

    1. Cat Post author

      Hi Sheri,

      That’s great to hear, glad you liked it!
      Iā€™d love to see the photo ā€“ you could send it to me via any social media (all of my links are at the top of my home page) or I could give you my email address?x

  5. Leora

    Hi šŸ™‚

    I’m on my second go at this, it’s baking now so hope it turns out well. What food colouring did you use? My first batch was liquid food colouring and it was awful, made the cake taste bad and could hardly see the colour. 2nd batch is dr otker gels and colour looks much better (at least in the batter) plus no bad taste!

    Thanks for the recipe!


  6. Lisa west

    I was wondering if I used the bigger 20cm Lakeland tins
    How much should I increase your ingredients by?

    1. Cat Post author

      Hi Lisa,
      The quantities in this recipe would make 2 20cm cakes. These would be quite thick though so depending on how thick you want each layer you could split it into 4 tins for a thinner layer and cook for maybe 15 minutes. x

  7. Mrs Miriam Harding

    How far in advance can I make this cake? Was hoping to make Friday, buttercream and fondant icing either Saturday or Sunday, for party on Tuesday. Is that too far in advance? And how can i store it?
    Did a trial run with this recipe today, really yummy

    1. Curly Post author

      Really pleased you like it! I think that would be slightly too long. I’d worry that the cake would start to become dry by then. Before the cakes are frosted I would wrap them in cling film or store them in an airtight tupperware. But once they are iced it would be tricky because the cake was too tall for my cake carrier and a box wouldn’t be airtight. If you could make the cake on Sunday I think it would be fresher.


Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.