Rainbow Cake!
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A delicious and bright rainbow cake with vanilla buttercream frosting, a pink drip and sprinkles!
Rainbow cake
Oh hellooo most requested recipe OF ALL TIME. I am not even joking, this recipe has been requested over and over again and I am ~finally~ posting it on to my blog! It’s taken a fair old time as I wanted to get it right!
I love all things cake, we all know this, but a rainbow cake is something else. The absolutely insanely bright colours, the sweet taste, and all things cute take it to a different level entirely! It is just glorious.
Disclaimer
So… I will say from the beginning that this recipe uses lots and lots of ingredients, and it is a humongous cake! Like, its 6 layers of cake, and all the buttercream in-between the layers, and all the decor on top!
And I will also say from the beginning… YES I KNOW THE RAINBOW HAS SEVEN COLOURS. This cake, is only six. When baking this cake, I just find making 6 colours so much easier, and you can see the obvious differences. I am not bothered about the seventh!
Red, orange, yellow, green, blue and purple… the main colours you need in your life. I did slightly compensate for the lack of seven colours by adding in a pink drip on the outside but we will get to that later.
Sponge
For this cake, I did make probably the biggest one tier cake ever. It’s about 8-9” in height, and uses so many ingredients. Because it is a six layer cake I decided to make it in two batches. So three layers at a time, so therefore you still only need three tins!
I made the cake a 600g mix, so that it’s super easy to split into two batches. The best way is to weigh 5-6 medium eggs, and get as close to 300g as you can, for example 312g, and then match the butter, sugar and flour to that weight.
Colour
Then, you mix it all together like normal, and then split into three bowls. It doesn’t matter which colours you do first, but I did red, orange, and yellow together, and then green, blue and purple.
The oven temperature is a bit lower than normal, as I don’t want the sponges to brown too much. This also comes somewhat from the brands of colours that you use! Red food colouring, orange food colouring, yellow food colouring, green food colouring, blue food colouring and purple food colouring. for the sponge mixtures!
Buttercream
Once my sponges are baked, I leave them to cool completely and freeze them wrapped in clingfilm over night so that they are easier to decorate the next day – but this bit is completely optional of course!!
For the buttercream, you do use 750g unsalted butter and 1500g icing sugar, which technically is a little obscene but the amount of servings from this cake is huge so please don’t be a negative Nelly about the sugar content!
I make my buttercream like normal by beating room temperature unsalted butter on its own for several minutes to make it really loose and supple, and then I gradually add in the icing sugar! I make sure to beat this for quite a long time.
White food colouring
You can do several methods to get whiter buttercream, by beating the butter on its own for a lot longer, or using a smidge of purple buttercream to counter act the yellow, but I love using this white food colouring! It looks amazing on my white chocolate drip cake and I haven’t looked back since.
I add a little at a time and keep beating it very well to make sure its really white and bright to contrast against the colours of the sponge! Making the buttercream whiter is completely optional of course though.
Decoration
When I am starting to decorate the cake, I dollop a few tablespoons of buttercream onto each sponge and smooth over, making sure to get the order of the colours in the sponges correct of course…!
Once you have layered each sponge you need to do a crumb coat by using as little buttercream as possible around the edges to seal in the spare crumbs from the sponges! I then chill the cake for a while to firm it up before adding another layer of buttercream on top.
I use a large metal scraper to decorate the sides of the cake, and a small angled spatula to also help cover the sponges – and its much easier and you are going to get a smoother finish using these as well!
Sprinkles and drip
Just as I have finished the buttercream I carefully press in some rainbow sprinkles to the bottom of the cake for a bit of colour and I just love the design – be warned, sprinkles will fall off at this point so beware! After this, I chill the cake again!
For the pink drip, I use white chocolate ganache with this pink food colouring added in. Its a super bright colour so you don’t need add too much and it means you get the best coloured drip ever!
Finishing touches and tips
I then pipe on the leftover buttercream and add on some more rainbow sprinkles and the best cake ever is finished! I am in love with the sponges and how bright and pretty it is – but the key point to make, YOU NEED TO USE GOOD QUALITY COLOURS.
Using supermarket colourings, will NOT work as well, or maybe at all… so please don’t waste ingredients by doing this! The colourings are 100% worth the investment as they last for so long! Any questions, leave them below in the comments and happy baking! x
Rainbow Cake!
Ingredients
Cake
- 600 g eggs (weigh eggs in shell) (about 10-12 medium eggs)
- 600* g unsalted butter
- 600* g caster sugar
- 600* g self raising flour
- 1/2 tsp red, orange, yellow, green, blue, purple food cololuring
Buttercream
- 750 g unsalted butter (room temp, not stork)
- 1500 g icing sugar
- 1 tsp vanilla extract
- 1-2 tsp white food colouring
Decoration
- 180 g white chocolate
- 75 ml double cream
- 1/2 tsp pink food colouring
- Rainbow sprinkles
Instructions
For the Cake
- Preheat your oven to 160ºC/140ºC fan and line three 8"/20cm springform tins with parchment paper and leave to the side for now.
- Weigh 5-6 medium eggs in their shells and get as close to 300g as possible (e.g. 312g)
- Then add 312g of butter and caster sugar to a bowl and beat until light and fluffy.
- Add in the eggs, and 312g of self raising flour and beat again until smooth.
- Bake the cakes in the oven for 30 minutes (or until baked - test with a skewer).
- Once baked, leave the cakes to cool in the tin for 10 minutes before removing to a wire rack to cool fully.
- (You can wrap the sponges in clingfilm once they have cooled and freeze over night to make decoratin easier but this is optional!)
Buttercream
- Once all of your cakes are cooled, you can make the buttercream.
- Beat the room temperature unsalted butter on its own for a few minutes to soften it and make it supple.
- Gradually add the icing sugar beating very well each time until its all mixed in.
- Keep beating and add the white food colouring and vanilla extract and beat for a few minutes.
Buttercream Decoration
- Using a 10" cake board, add your first sponge. I start with purple as its the bottom colour.
- Add a couple tablespoons of the buttercream on to the sponge and smooth over. Repeat this with blue sponge, then green, yellow, orange and finally red at the top.
- Using a small amount of buttercream, smooth over the sides of the cakes and fill in any gaps and create a crumb coat.
- Refrigerate or freeze the cake on the board for an hour or so to chill and firm to make the next stage of decorating easier.
- Once chilled, add on lots more buttercream around the sides of the cake with a small angled spatula, and smooth over using a large metal scraper until the sides of the cake are smooth like in the photos!
- Carefully press some of the sprinkles into the bottom of the cake using the palm of your hand to create the sprinkle effect!
- Once this has been done, refrigerate again whilst you make the drip!
Decoration
- Add the white chocolate and double cream to a bowl and heat in a microwave in short 10 second bursts stiring well each time.
- Once melted and combined, add the pink food colouring and mix until smooth!
- Add the pink ganache to a piping bag and carefully cut off the end and drip down the sides of the cake. The more you push over the side of the cake with the piping bag, the further it will drip!
- Add the leftover buttercream to a piping bag with your favourite piping tip and pipe swirls of buttercream onto the top of the cake (like I have done in the photos)
- Finally sprinkle on some etra sprinkles and leave the cake to set in the fridge fully.
- In the hot weather I store the cake in the fridge until it has been portioned.
Notes
- This cake lasts 4-5+ days once made!
- The colours that you use and what order are up to you, this recipe is just how I did it! You can swap up the order or whatever you prefer!
- You should avoid supermarket colours as they are not strong enough.
- In this recipe use:
ENJOY!
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J x
© Jane’s Patisserie. All images & content are copyright protected. Do not use my images without prior permission. If you want to republish this recipe, please re-write the recipe in your own words and credit me, or link back to this post for the recipe.
Hi Jane!
Sorry it’s me again, Carlota I just really need the answer to this question. Can I use vegetable oil instead of butter on my cake so when I put it in the fridge it doesn’t harden?
Sorry again for disturbing.
Thank you!!!😘
Hi!
So I have a question, can I use vegetable oil instead of using butter so when I put my cake in the fridge it doesn’t harden?
Thank you!
Good afternoon, how long does it take to defrost the cake ready to eat? Also if I wanted to make into a 6inch what would be the measurements and time to cook please?
Hi Jane and Team,
I’m making this at the weekend for my daughters 4th birthday. When freezing do they need to be defrosted before decorating. If so how long would they take to defrost please.
Many thanks. Looking forward to the end result.
Made this for my daughter’s 11th birthday. Turned out amazingly, I used rainbow dust gel food colouring bought from Lakeland which was great value and worked great. Didn’t do the drip as she wanted it decorated differently. It is a huge cake though, gave everyone a small slice and they still struggled to finish it 😂
Hi! Would using cream cheese frosting be okay for this cake?
Ps love this recipe made it for my daughter’s birthday last year and just wanted to try and change it up abit because she wants it again!
Yes, it would work well but that means the cake needs to be stored in the fridge x
Thank you so much for yet another wonderful recipe. I made this for my daughter’s 4th birthday and she LOVED it! I only did 4 layers as it was just for three of us but still looked so impressive x
I need to make my cake 2 days before the party. Would I be best off doing the buttercream and sprinkles the morning of the party? I’m worried the colours of the sprinkles will bleed. Or even could I just do the buttercream in advance and then the sprinkles in the morning to save time?
Hiya! It should be fine, though if you’re worried then add the sprinkles the morning of! Hope this helps! x
Hi, I made this and everything came out fine expect the pink drink it went so gloopy and almost like slime and just hasn’t set like ganache why could this be?
Hiya! This can be due to the type of food colouring used, you can try adding a tad more cream to make it more runny! Hope this helps! x
Hi Jane, I love your rainbow cake!
How tall would this cake be? As I’m looking to purchase a cake topper. Also do you have an egg-free sponge that suitable for this recipe? My daughter has food allergies
Many thanks x
Hi Jane and team, will be making this cake next month. When mixing in the colours, I;m thinking it will take a good mix to blend colours. So, is that ok? always iffy about the “don’t over mix” rule, Thanks
Hiya! Yes this should be fine, just mix until combined then leave them! Hope this helps! x
Hi Jane
If I was going to do this as a 6 layer smaller 6 inch cake could you let me know what the ingredient ratios would be and the cooking time.
Thanks
Hi Jane I’m making this for a combined birthday. However we don’t have self raising flour where we live. And there’s conflicting diy baking powder:flour ratio on Google. What’s your advice please?? Much appreciated thank you!
Hiya! For every 150g plain flour used, whisk in 2 level tsp baking powder before using. Hope this helps! Team Jane 🥰 x
Hey, I’m going to make this for my daughters first birthday. I tried clicking on the link for the white food colouring but it doesn’t work anymore, could anyone point me in the direction please? Thank you.
I too would like to be advised so following. Thanks!!
Hiya! The link should be working now. Hope this helps! x
I made this for my daughters birthday. First time making a layer cake or a rainbow cake and it came out PERFECT what an awesome recipe it tasted fab!
Hi, if I were to bake the cakes and pop them into the freezer, can I leave them for a few days before taking them out to decorate? My weekday schedule is busy therefore I was hoping to bake the cake a week before it is needed and finish the decorating almost 5 days after! Thanks!
Yes absolutely, you can freeze them for up to 3 months in total! Hope this helps x