How to Make a Rainbow Cake

Here’s how to make a beautiful, jelly bean rainbow cake for an exciting addition to a colourful, birthday party! Fun and unique and not as hard as it looks to create!

When I first saw this rainbow cake idea a couple of years ago I was amazed by it, but completely put off making it because of the complicated instructions that I found. Most seemed to suggest freezing layers of cake, cutting the tops off and other labour intensive stages that seemed much too difficult! But when Cakie decided she wanted a Willy Wonka birthday party, this seemed to fit the theme perfectly, so I decided to just have a go and hope for the best! It really wasn’t as hard as I expected and I cut corners with an easy cake recipe and by using store bought icing!

 

Here’s what I did:

 

RECIPE

 

I trebled my trusty go-to Victoria sponge recipe, with the aim of making 6 thin layers of cake. It’s lovely and easy because it is mixed all in one- perfect!

 

[Check this helpful link to convert grams to cups!]

 

9 eggs

540g self- raising flour

540g softened butter

540g caster sugar

1 teaspoon vanilla essence

2 teaspoons baking powder

gel food colouring

dash of milk

 

  • Preheat the oven to 180 degrees C and grease two 7 inch cake tins with removable bases
  • Mix all the ingredients (except the food colouring) in a large bowl until smooth, using using electric beaters

 

  • Divide the mixture into 6 equal portions, each in a separate bowl. (I did this by eye, by first splitting it into 3 portions, then dividing those in half. Of course you can do it however you like, but this seemed easier and a good way to ensure each portion was the same size.)

 

  • Add 1 teaspoon of gel food colouring to each bowl of mixture and mix in really well. I used Wilton brand and they were really vibrant! I used red, orange, yellow, green, blue and purple. (Yes, I know food colouring isn’t healthy, but I do think birthdays are special, one-off occasions! The natural colourings, though a much better option, just don’t look as vibrant at all.)
  • Bake two cakes at a time for 25 minutes. Insert a metal skewer to the middle of the cake to see if it comes out dry. If it still has doughy cake mixture on it then leave it for 5 more minutes and try again. You don’t want these to over-cook as that will increase the crumbliness, which makes the decorating difficult.

ICING:

 

  • When cool, place the purple layer on a cake stand ready to start the sandwiching of the layers together! I borrowed a tip I’ve seen on You Tube in the past, of tearing 4 strips of paper and sticking them under the edges of the cake (as you can just make out in the photo above). This is great for catching icing mistakes, as when you pull the paper out later it takes all the mess with it!

 

  • I totally cheated and bought 3 tubs of Betty Crocker’s vanilla buttercream icing/ frosting as I didn’t want the stress of getting the perfect icing consistency and knew that I could mess up a beautiful cake by getting it wrong! Icing IS really easy to make though, so if you’re not as lazy as me, try this recipe from all recipes.com.

 

  • I used a small amount between each layer of cake to sandwich them together and secure them. Make sure you use enough so that it can be seen when cut, as this adds to the visual impact!

DECORATING:

  • When all the layers are sandwiched together, create a “crumb coat” of icing over the entire cake, i.e. a thin layer of icing that will catch all the loose crumbs. It doesn’t matter if this first layer is a bit messy, just ensure it’s fairly even.
  • Either put it in the fridge (if you live somewhere hot) or leave out on the side for a couple of hours, to dry out and set a little. Then come back and add the final layer of icing. By keeping it simple and white it really adds to the WOW when the colours are revealed inside!
  • When it as completely covered I added a packet of jelly beans all over it and made a quick number 4 topper by writing the number in glitter glue on some card and sticking it to the middle of a lollipop.

The birthday girl was thrilled with her whacky, jelly bean rainbow cake and completely amazed to see the colours inside it! This cake was MUCH easier than I thought it was going to be and I would definitely make it again. Cutting corners by using store bought icing and not bothering to freeze it in-between icing definitely removed some of the stress factor and made it a manageable morning’s project.

Have you ever tried making an unusual birthday cake? Please share your ideas in the comments!

35 comments to How to Make a Rainbow Cake

  • Fabulous! And seems doable. How many does this serve, would you guess? 7″ layers seems small, but then, there are six of them!

    • It was HUGE!! There were about 20-25 people eating this and I still had 1/3rd of the cake left over! Each piece is so tall that you either cut the piece very thinly, or you can cut it into 3. I used 7″ because that’s what I had, but I’m sure 8″ would be great too

  • I made a similar one for my daughter last year using Jell-o mixes to colour the layers. I wasn’t able to make all the colours of the rainbow, but it still had the desired effect and it added some nice, subtle flavour to the white cake. I just iced mine with cool whip so it would have more of a cloud effect (and I was too lazy to make icing!)

  • Ruth Sadler

    Thanks this is perfect, been looking for a similar recipe for my daughters 2nd birthday at Halloween, definitely going to give it a go!!

  • Karen

    Just made ladybird cake for my daughters birthday tomorrow – I have had many request for this cake maybe next time – looks fab

  • FOr anyone making this for a child or child’s birthday, please do your research. I think it is adorable and cute, but please keep in mind that petroleum based dyes can cause major issues for many kids- ie hyperactivity. It is not a sugar high after a birthday party- it is usually the effects of food dye. My child gets nightmares after eating food dye, wets the bed, becomes aggressive, can’t focus and hyperactive. Proceed with caution.

    • I agree. Know your own child. Our food dyes in the UK have stricter regulations and I’m perfectly happy using them. No side effects for any of us or our guests thankfully :-)

  • Anonymous

    Very cute! Tip: Buy regular frosting in a can (not whipped), then use your hand mixer and whip it for a seconds. You will get twice as much frosting for the price of one can.

  • So lovely Anna…i made something similar for my teen’s Birthday this year after a ‘strong’ request lol! And Birthday’s happen only once a year so i think any hyperactivity is perfectly acceptable! As long as you are aware it might happen than i don’t think it is a problem. My eldest has always had this issue with colouring but Birthday’s have always been an exception and of course it doesn’t happen to every child…let them have some fun and joy i say…and that cake certainly provides that!!!

  • I really love these cakes. I’m going to do one for my son’s 3rd birthday. Wish me luck! x

  • Very nice, thanks for sharing.

  • So glad you’ve posted this, it’s on my wish list for my twins’ 2nd birthday party in November! Good to know it’s do-able in a morning – I wasn’t looking forward to trying to cram it in the freezer…

  • I’d love it if you’d link this to my kids in the kitchen post – we link up every tues! pinning!

  • Oh how yummy! I’d love for you to come share this at our Pinteresting Party!

  • so pretty! we made the same type of cake a couple years ago with a similar process to yours… though did make the layers a day in advance and freeze them. (ours is here: http://paintcutpaste.com/rainbow-art-party) i found them easier to frost when they were more firm. i LOVE all of your party pics on instagram. i’m sure it was an amazing and memorable day!

  • am i able to do this in a retangler tray ?x

  • Anonymous

    ooh… a rainbow cake. okay random.

  • Anonymous

    I like the idea of a rainbow cake but the problem is I only have one round tin. Is there any way to make it easier to bake, without buying more tins? If I have a big tin, can I bake them all at once? Is that possible? Please reply if you can, thanks.

    • No I don’t think you can make them all at once as the cake batters would merge together and you couldn’t keep the sizes determined. You could instead stir the colours through a little to make a marbleised effect.
      Otherwise just use the one tin and give it a quick wash and dry then re-use it to bake all 6 colours! It will take a while but not a problem

  • Puffpuffadder

    I made this cake for a nativity and it was perfect! (though i only had one tin so it took a while lol) – thankyou

  • That cake is gorgeous! This may be a silly question but after converting the recipe to cups and figuring out what I needed to add to make my regular flour into “self-raising” flour, it appears I would need to add an additional 4.5 teaspoons of baking powder to the 2 teaspoons already listed in the recipe. So, we’re talking 6.5 teaspoons total (2 from the recipe + 4.5 teaspoons to make the flour self-raising.) Does that seem correct? I wanted to be sure. I bake a fair amount and I’m not sure I’ve ever added 6+ teaspoons of baking powder or baking soda to a single baked good. I just want to be sure as I want the cake to be as perfect as possible for my son’s 2nd birthday party. Thank you!! Sarah

    • Oo Sarah I am so scared to answer in case I mess this up for you! I always mess up when converting things and adding in extras. You definitely don’t need that much baking powder, eek! The best advice I can give you is to find a favourite Victoria sponge recipe and simply triple it. Would that be safer perhaps? Let me know how it goes!

  • One simple thing that you need to consider is color. Your personal chanel bag online should blend or match with most of your outfits. Therefore, it is very recommended for you to choose a hermes bag outlet with mid-range colour. Try to not purchase a handbag with extreme colours, such as red or ice blue. It is a good idea for you to buy a cheap louis vuitton handbags with neutral colour, such as black, chocolate, turquoise, purple, and many other neutral colour. Neutral colours will be able to blend with most omega watches online outfits.

  • Anonymous

    I made this last month for my daughter’s first birthday and it was an absolute hit! Everyone ‘ooohed’ when I cut into it, so pleased I took the leap to make it, it was much easier than I feared it would be. Thank you for the great instructions x

  • Hello, I love this cake and the way you have done it. Out of all the recipes on the internet this is my favourite. I would like to get the colours rights when I try it as they are expensive. Could you confirm the colour names please? There are several different names for each colour with Wilton. Were they just as you say or did they have Christmas Red or Lemon Yellow for instance.

    Much appreciated

  • izzie

    I am making this for my Nan’s birthday party tomorrow will it keep till then?

  • I made this for my son’s birthday and everyone loved it! There’s a picture on my blog: http://georginasnewthings.blogspot.co.uk/2013/02/rainbow-cake.html

  • Anonymous

    Wow i just had my daughters 5th birthday party today and this cake was an amazing hit!! The kids thought it was brilliant and i had lots of comments from the parents :). This was actually the first birthday cake i have ever made so I was quite proud! I too also cheated and used the betty crocker icing – SO EASY!! but i did have a bit of trouble with the layers, perhaps my oven was too hot or i put one too many eggs in but i got a film of egg on the top of each layer when it was cooked which i had to peel off, was odd. Also – I used the cheap food colouring from the supermarket not the wilton gel type. I was very very worried that my colours wouldnt be as vibrant but they were perfect!! i saved myself a lot of money as well as the wilton colours are around $5 each and normal food colouring is $1.30! Thankyou for your easy to follow recipe!