From M&S to Tesco, from Sainsbury’s to Morrisons, I have tried and tasted more rainbow cakes than I’d like to admit, and here are my favourites.
The kids' party food ideas have been decided, the goodie bags are packed, and the soft play venue has been booked months in advance - but what about a birthday cake?! If you’re still undecided about which birthday cake to buy your little one for their special day, we (me and my kids, that is) have tried and tested a range of different rainbow cakes from various supermarkets to find the best of the best.
When it comes to choosing the best birthday cakes for kids, my go-to is to make my own birthday cake - be it a rainbow cake from scratch or a DIY caterpillar cake. I really do like baking my own and watching my kids’ faces light up when they see the hard work I’ve put in. However, sometimes there is no time for playing Mary Berry or slaving away in the kitchen for hours and a shopbought cake is the answer.
Being Food Editor on GoodtoKnow for well over 10 years means that I have a wealth of knowledge when it comes to compiling a list of the best birthday cakes and in this roundup, each and every cake has been ordered, sampled, and reviewed by yours truly. Of course, everyone's taste buds are different but I like cake. I like to bake cake, eat cake and I’m a bit of a cake snob (there, I said it) so you can trust that what I’ve chosen is going to be quality and good value for money too as kids' party planning is all about keeping to that budget… she says.
PS... GoodtoKnow's Food Writer has tried and tested the best supermarket caterpillar cakes for those looking for more kids' birthday cake options
Where to buy the best rainbow cakes and more
- M&S: Push the boat out with one of M&S finest birthday cakes this year
- Ocado: Delicious rainbow cakes from M&S, party tray bakes, and decorate your own
- Tesco: Themed kid's birthday cakes, rainbow, drip, chocolate, and much more
- Morrisons: Birthday cakes for kids including good value for money rainbow cake
- Sainsbury’s: Choose from rainbow cakes, mouthwatering chocolate cake and more
- ASDA: Great value for money rainbow cake as well as other celebration cakes too
Best rainbow birthday cakes - quick list
RRP: £14.50 | Serves: 12-16 | Available: 3 days to collect
The raspberry jam filling stole the show for this cake making the overall cake sponge super moist, fruity in flavour, and soft in texture. A different take on the usual rainbow layers as this one includes a green layer which surprised us.
RRP: £14 | Serves: 20 | Available: Online and instore
It’s big, bright and brilliant. A good value-for-money cake that isn’t too sweet or too heavy on the buttercream. A great base cake for those who want to personalise or add their own flair to a shopbought cake.
RRP: £16 | Serves: 8 | Available: Online via Ocado
Don’t be deceived by this small rainbow layer cake, it certainly packs a punch of sweet flavour thanks to the creamy, smooth, vanilla-infused buttercream. A super sweet flavour with defined rainbow layers.
RRP: £14.50 | Serves: 10 | Available: Online and instore
For smaller gatherings, this cake serves 10 but still has distinct rainbow layers with plenty of colour. The vanilla buttercream coating and filling dominate on flavour certainly making it ideal for those with a serious sweet tooth.
RRP: £15 | Serves: 16 | Available: Online and instore
This eye-catching rainbow cake certainly doesn’t disappoint when it comes to decoration and has an overall homemade look about it. A combination of raspberry jam and a vibrant blue buttercream layer sandwiches each coloured sponge together making it a super sweet option.
RRP: £16 | Serves: 16 | Available: Online via Ocado
The rainbow cake alternative, this cake has the ‘wow’ factor thanks to its immaculate pastel buttercream topping. The plain Madeira sponge is soft and moist and pairs nicely with the pastel-coloured buttercream inside.
Best supermarket rainbow birthday cakes
Morrisons Rainbow Celebration Cake
RRP: £14.50 | Serves: 12-16 | Available: 3 days to collect
The Morrisons Rainbow Celebration Cake certainly got us all talking not just because of the sprinkle-tastic appearance but the raspberry jam filling too as most rainbow cakes we tried opted for vanilla buttercream filling. The raspberry jam added a lovely, fruity taste to the cake, and the sponge itself was moist with a soft, spongey texture.
When I cut into the layers however I was a little underwhelmed by the colours as they weren’t as bright and vibrant as some of the other cakes, however saying that my kids were delighted to see a green layer, which none of the other cakes had. The buttercream used to coat the cake and hold the sprinkles in place was minimal meaning the cake wasn’t overly sweet, leaving the raspberry jam flavour to dominate in each bite.
My six-year-old said: “I like the jam, it’s tasty. A very good cake and the green layer is very cool. This is my favourite cake. Can I have another slice?”
Morrisons Rainbow Celebration Cake - £14.50 - Morrisons
The BAKERY at ASDA Rainbow Jazzie Cake
RRP: £14 | Serves: 20 | Available: Online and instore
Asda’s Rainbow Jazzie Cake ticked a lot of boxes for me. Firstly it was big, and certainly a good size for slicing up and adding to party bags - I cut it into 20 ‘squares’ instead of triangular slices and felt like there was plenty of cake to share with this one.
And at £14, it’s one of the best value-for-money cakes in this taste test. The sponge was light, with subtle vanilla flavour thanks to the buttercream, colourful layers evenly baked, and sprinkles that gave it the ‘wow’ factor. Plus it wasn’t too heavy on the icing either so wasn’t overly sweet. The other thing I liked about this cake is that it’s a great base for those who like to add their own flare as the top could easily be personalised with cake toppers, numbered candles, etc.
My four-year-old said: “It’s such a big cake covered in so many sprinkles - look at all of them…one, two, three, four, five... 1,074! I love the sprinkles. Wow. The pink layer is my favourite.”
The BAKERY at ASDA Rainbow Jazzie Cake - £14 - Asda
Marks and Spencer Rainbow Layer Cake
RRP: £16 | Serves: 8 | Available: Online via Ocado
One of the smallest cakes we taste tested, the M&S Rainbow Layer Cake serves 8 which means it's a good choice for smaller birthday parties, or if you’re serving cupcakes, doughnuts, or other sweet treats alongside it. A very neat rainbow cake with defined rainbow layers and colours.
The buttercream was the highlight for us as it was creamy, smooth, and infused with vanilla, however, it does mean that this cake is extra sweet so brace yourself for the full on sugar rush. M&S also has a bigger rainbow layer cake which serves 12, can be preordered directly on the M&S website, and includes an extra layer of sponge cake too if you need something bigger.
My six-year-old said: “It’s small but I like that it has sprinkles on the side and not on the top, just that swirly pattern. It looks nice and the icing is good.”
M&S Rainbow Layer Cake - £16 - Ocado
Sainsburys Rainbow Layer Cake Taste the Difference
RRP: £14.50 | Serves: 10 | Available: Online and instore
There is something homemade about the look of this cake which is a great choice if you want to tell everyone you made it yourself - don’t worry, we all do it now and then. The colours are clear with distinct layers and a fluffy sponge. This cake is a similar size to the M&S Rainbow Layer Cake meaning it's a good choice for smaller, intimate birthday parties.
This cake is quite heavy on buttercream both on top and layered in the cake, but it does add further flavour to the cake overall - just keep in mind for those who aren’t too keen on buttercream as it might be too much. Priced at £14.50 it’s at the lower end of the budget when it comes to the cost of rainbow layer cakes.
My six-year-old said: “I like the colours inside this cake - the dark purple is very cool and it doesn’t matter that there are no sprinkles on top because there’s more room for candles.”
Sainsbury’s Rainbow Layer Cake Taste the Difference - £14.50 - Sainsbury's
Tesco Rainbow Cake
RRP: £15 | Serves: 16 | Available: Online and instore
Decorated differently from the rest, this rainbow cake by Tesco has a fun homemade vibe with the vibrant blue buttercream which certainly makes it stand out from the crowd. Like the Morrisons cake, this one is also layered with raspberry jam which makes it taste much fruitier and sweeter than the rest.
This cake was quite heavy on the buttercream which I personally wasn’t so keen on as it was very sweet, however, the size, overall look, and moistness of the sponge made up for it. Plus this cake is decorated for you, so you won’t have to add anything extra to make it stand out. The kids liked this one more than me predominately because of the way it was decorated.
My four-year-old said: “I like the rainbow on top - is it chocolate? Can I eat it? The blue icing is good… I’m just going to try some with my finger.”
Tesco Rainbow Cake - £15 - Tesco
Marks and Spencer Under the Rainbow Cake
RRP: £16 | Serves: 16 | Available: Online via Ocado
Ok, so this is technically not a rainbow layer cake as the sponge itself isn’t rainbow, however, the decoration is and the buttercream inside the cake is rainbow too. Let’s call it a rainbow cake alternative for those of you who want the rainbow look, but not too much of the coloured sponge.
A really lovely cake from M&S with a light, sweet Madeira sponge, soft buttercream, jam filling, and eye-catching pastel colours. Similar to the Tesco cake, all the decorating has been done for you, all you have to do is add the candles for the birthday kid. This cake certainly has the rainbow ‘wow’ factor when it comes to the overall look - just lacking in the rainbow centre.
My six-year-old said: “I love the colours of this cake and the rainbow and little white bits on top. The icing is clever and the inside with the coloured buttercream is great too.”
M&S Under the Rainbow Cake - £16 - Ocado
How we tested the best rainbow birthday cakes
Before the taste test began, I wanted to make sure that I had rainbow cakes from each supermarket that sold them so it was a case of firstly researching, sourcing, and ordering each cake whether online or shopping in-store.
Once I had all the cakes, I needed to make sure each cake would be assessed with the same criteria so I created taste test sheets marking the price of the cake, how many people it served, where you could buy it (online, instore or both) as well as general appearance, first impressions, flavour, taste, texture, and any other comments on why that cake stood out above the rest, or what made it the best rainbow cake and worthy of being included in this roundup.
After looking at the decorations, and the size and servings of each cake it was about cutting the cake to reveal the rainbow layers inside, tasting and noting down how even the layers were, what the buttercream looked and tasted like, how sweet or not sweet it wasted, flavour combinations - for example, some had raspberry jam filling others didn’t - and so on.
Then it was time to get the kids involved - which, of course, those of you with kids can imagine was rather chaotic with six rainbow cakes to choose from. However, the children were both very good at trying small pieces of each cake and saying what they liked or didn’t like about it - but most comments from my two were positive. Kids and cake, eh? Then they abandoned ship and had a serious sugar high so we ended up taking them to the park to burn off some energy leaving a massacre of cake crumbs and sprinkles across our kitchen table to deal with when we returned.
What was your favourite rainbow cake?
The cakes in this roundup are in priority order with The BAKERY at ASDA Rainbow Jazzie Cake being our favourite and the Morrisons Rainbow Celebration Cake being a very close second. The M&S Under the Rainbow Cake was a bonus cake I tested as an alternative option which proved popular with myself and my testers too.
What was your least favourite rainbow cake?
Unfortunately, the Sainsbury’s Rainbow Layer Cake Taste the Difference was our second least favourite and despite its vibrant decorations, the Tesco Rainbow Cake was our least favourite.
What’s the best way to cut a rainbow cake?
As rainbow cakes are very sweet it’s probably best to give small thin slices of this type of cake, especially to children as there is a whole lot of sugar in each one. I like to cut my cake into squares, instead of the usual triangles. It’s a great way to stop waste, and get the most out of your cake - and it means perfect party bag-sized pieces of cake.
Feeling inspired to make your own rainbow layer cake or how about some rainbow cupcakes to serve alongside your shopbought cake? And don’t forget to have a look at our easy cake decorating ideas for those of you who want to transform and personalise any of the cakes above.
You might also like our list of Frozen birthday cake ideas or your children might prefer these Bluey birthday cake ideas.
We've also got plenty of first birthday party ideas for those of you thinking of celebrating your little ones' big day, not to mention kids' party games everyone will love, as well as 13th birthday party ideas for your pre-teen.
