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how to make | a rainbow unicorn cake

When I say how to make it, I mean, how to make it from a real, average baker’s point of view. And this post will give you an idea of what really happens when an average baker tries to make a Pinterest style recipe for a rainbow unicorn cake.

My daughter wanted a rainbow unicorn cake. So, because I’m soft in the head and heart, and have so much time on my hands, obviously, I decided she would have one for her birthday.

This is what I got to by Googling rainbow unicorn cake. This was my goal.

I used this recipe here, for those of you looking for an actual recipe. Here’s a few things you need to know about this zeppelin of a cake:

  • You’re looking at SIX packs of butter, one kilo of sugar, and two kilos of icing sugar (if you go down the full buttercream route). You will feel queasy in Aldi putting all that in your trolley, I tell thee.
  • This took me a week to make.
  • All in all, it cost about £35.00 because, unless you have them in stock, you need some pretty professional food colourings, icing bags and all sorts of guff to style it with
  • Slicing it and storing it is an absolute mission
  • Most importantly though, you might cry with joy when your child sees it for the first time. The look on my daughter’s face was absolutely worth the pain!

So, you’ve made your FOUR sickly coloured sponge cakes. And, mine were all a bit wonky and sad. The next stage will make you appreciate those clowns who tiled your bathroom or built your extension so much. Because you have to stick it all together and smooth it out, using buttercream. My top tip here is a rotating cake stand, six quid from the mighty Wilkos. appetising! You then bang it in the fridge for a while, let the sugar concrete set, and then do it again, to try and make it straighter. I think this is called crumbing.

That same evening, still high from my fingerfulls of buttercream, I embarked on covering the thing with fondant icing. You measure the cake from side, over the top, to side, with string and then knead and roll out the icing to that circumference. But, have you ever tried to lift a sheet of floppy confectionary which is about two foot in circumference, with just two hands and a spatula?

I managed to get it on, only losing half my mind and a few tears, about an hour later.

Now I had something resembling on of Jamiroquai’s old hats, discarded after a Malibu and Coke bender in Malia, to try and shape into a perfectly symmetrical, white cylinder. By this time, I was cackling like a crone, and sculling cider, just to keep on an even keel.

But, after a one-woman recreation of that scene in Ghost, and some enthusiastic smoothing, it was more Stromtrooper’s helmet than face of a unicorn, but I decided to press on with the flair bits. It was then that it really started to look like a unicorn.

What am I saying? As IF it looked like a hairy white horse with a horn and a blue rinse. But it did start to look like the picture. A bit. Here’s what I did:

  • I sprayed an ice cream cone from Aldi with edible gold lustre spray (seriously, this exists and I feel duty bound to tell you that it HAS TO have some use in spicing up your love life at some point. Oh, the possibilities!)
  • I literally went insane with a piping bag and another kilo of buttercream, creating a tangly mane for the creature. It’s amazing how you can stick sugar to sugar vertically without much talent
  • I made ears out of fondant icing, which looked like fried eggs and tasted like unicorn’s ASS, but stayed on the cake with the aid of strategically placed toothpicks
  • I piped little eyes onto the beast, wonkily, with the shaky hand of a woman in need of another cider
  • I finished it all off with a liberal dusting of pink edible glitter. Glitter, I can confirm, does indeed make a silk purse cake out of a sow’s ear cake

And here she is, in all her glory. Probably weighing at least a stone and singing like the siren of diabetes,  the rainbow unicorn cake!

My goodness I was so proud of it, and then SO nervous. Because, like that bin bag in your loft which smells, god knows what it was going to look like when I cut it open.

The day of the party dawned (literally, three minutes after I had finished humping buttercream around) and the party itself, which you can read about here, was an amazing success. But, how would the cake go down?

Small children swarmed to it, blithely ignoring the enormous knife we had to select to cut the thing open. Tibbs vibrated with happiness, finally, I had actually made good on a parental promise! YES! I MADE A RAINBOW UNICORN CAKE!

Then I cut it open. The suspense (and the weight of the cake) was killing me.

Yup. It’s not perfect. The cake droops like Magnum’s moustache into a pillow of buttercream on each layer. But, it was not only edible, it was tasty too! You couldn’t eat more than a slice. And that’s me who can eat three Creme Eggs in one go saying that.

We actually sliced it into colours rather than thin slices of four colours, which would’ve been so hard to eat. It stored pretty well under its cling film prison, and kept for just under a week. We did have to throw half of it away, even though I had plans to make the campest ever trifle with the stale sponge.

So, the verdict?


Don’t be scared of failure, or of it not being perfect. Look at this rainbow unicorn cake. It’s proper amateur. But my daughter just saw the good bits, and the fact that mummy made it, and that it was everything she ever wanted in a cake.

So, even if your kid asks for a replica cake of Justin’s House with an edible Robert, or an Owlette flipping the bird at Romeo from the comfort of her OwlGlider cake, give it a shot. If I can do it, you can!

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  1. Rachel Rachel

    It was a tasty piece of baking my friend!

  2. (bows down) great work! She must have been thrilled. Our party was in the park and given the same request went with a more manageable/transportable two layer vanilla cake with pink glitter and a plastic Princess Celestia on the top!

  3. IT’S AMAZING! This reminds me so much of the pain when I made Freya’s rainbow cake for her 4th birthday. We were up til 2am. It was horrendous!

  4. Jamiroquai’s old hats 😀 This is BRILLIANT, don’t sell yourself short! Amazing work x

  5. Tracy Neville Tracy Neville

    Brilliant cake and superbly funny article. I am a hobby baker but boy can I relate to your trials while making this. Well done you and you should feel very proud.

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