This dark rainbow unicorn birthday cake is the perfect centrepiece for a unicorn-themed party. Three layers of vanilla buttermilk cake are frosted with purple-tinted white chocolate buttercream and decorated with Midnight Magic Sprinkles. Shards of unicorn candy bark and a purple candy melt drip finish it off perfectly.
Table of Contents[Hide][Show]
- Unicorn Birthday Cake Inspiration
- What you’ll need
- How to make a vanilla buttermilk layer cake
- How to make Unicorn Candy Bark
- Instructions to make white chocolate buttercream frosting
- How to assemble & frost this Unicorn Cake with Candy Bark
- How to decorate this Unicorn Cake with Candy Bark
- My tips for making this unicorn birthday cake
- Unicorn Birthday Cake with Candy Bark
- Pin this Unicorn Birthday Cake recipe for later
- Other birthday cake recipes you might like
Unicorn Birthday Cake Inspiration
I made a cake!
I’m really rather proud of this cake, too.
This cake was inspired by a jar of Midnight Magic sprinkles I spotted in the supermarket. It also used candy melts and gel food dye leftover from an Easter candy bark recipe I’d made earlier this year, which were taking up valuable cupboard space.
So, this dark rainbow unicorn birthday cake extravaganza was born, and boy, my kids were impressed! You should have seen their faces!
The cake isn’t as sweet as its appearance suggests, and it serves 12, so it would be perfect for a small birthday celebration.
What you’ll need
- butter
- caster sugar (granulated will work just fine too)
- free range eggs
- plain flour
- baking powder
- salt
- buttermilk
- vanilla
- candy melts in your favourite colours
- white chocolate
- icing sugar
- purple gel food colouring
- Midnight Magic Sprinkles
Jump to the full, free printable recipe below for quantities.
How to make a vanilla buttermilk layer cake
- Cream together butter and sugar until well incorporated. This cake has less butter than a cake usually does, so it won’t get light and fluffy like you are used to.
- Add in the room-temperature egg whites and the whole free-range egg. Beat until light and foamy.
- Sift together the flour, baking powder and salt.
- Add the vanilla to the buttermilk and add in increments, along with the flour mixture, beating well after each addition.
- Scrape down the sides and beat until well incorporated.
- Weigh out the batter and divide evenly between three greased and lined 6-inch cake tins. Bake until golden.
To top my cake, I’ve used shards of unicorn candy bark made from candy melts. You could just go for a simple white candy bark studded with the Midnight Magic sprinkles or opt for a more colourful decoration by adding pink and purple candy melts. I find the coloured candy melts cool down and harden really quickly, which is why there are no step-by-step photos of the process – there was no time to stop and take photos!
How to make Unicorn Candy Bark
- Melt your candy melts in a microwave as per the package instructions or in a heatproof bowl suspended over a pan of barely simmering water.
- Using a spatula, spread out the melted white candy melts onto a silicone mat or piece of non-stick baking paper.
- Add a little vegetable oil to the coloured candy melts if they’re too thick, and drop small spoonfuls all over the top of the white layer.
- Swirl all the colours together using a wooden chopstick.
- Decorate with a few tablespoonfuls of Midnight Magic sprinkles and refrigerate until hard.
- Remove the silicone mat and cut the unicorn candy bark into shards with a sharp knife.
Instructions to make white chocolate buttercream frosting
- Cream together the softened butter and icing sugar with a hand blender.
- Melt white chocolate in a heatproof bowl suspended over a pan of barely simmering water. Leave to cool to room temperature.
- Add the cooled melted white chocolate and the double cream to the icing sugar mixture.
- Beat well until light and fluffy.
- Add your colouring – I used two squirts from the gel colouring tube.
- Continue to beat until the frosting is light and fluffy.
How to assemble & frost this Unicorn Cake with Candy Bark
- Using a serrated knife, slice off the tops of the three cakes so they provide an even surface for layering.
- Spoon a little frosting onto the cake plate to keep the cake in place. Arrange greaseproof paper around the edges to protect the cake stand from getting too messy while you frost the cake.
- Place the first cake, cut side up, on the cake stand. Spread with a generous layer of frosting.
- Arrange the second cake, cut side down, and repeat with another layer of frosting and the last cake (put this one cut side down too).
- Cover the entire cake with a thin layer of frosting – the crumb layer – and chill for 30 minutes to set.
- Frost again with another layer of frosting, smoothing, if desired, with a long ruler (no fancy equipment needed!).
How to decorate this Unicorn Cake with Candy Bark
- Decorate the bottom edge of the cake with some Midnight Magic Sprinkles. Use a spoon to help put them in place, pressing them slightly into the frosting.
- Melt some purple candy melts with a little double cream. Cool.
- Place the cooled candy melt mixture into a disposable icing bag (you might need two as I find if it’s too hot, it melts the seam and leaks).
- Carefully pipe the purple drip around the top edge of the cake, piping a little more and less along regular intervals to drip down the sides.
- Use the remaining Midnight Magic sprinkles to decorate the top of the cake.
- Using a sharp knife, cut one-centimetre slits in the top of the cake for the shards of unicorn candy bark.
My tips for making this unicorn birthday cake
- I’ve also recently discovered that candy bark doesn’t always cut into the shapes you want it to, which is why I’ve made a big batch for this recipe. Any leftover unicorn candy bark could be put in a party bag for kids.
- This cake perfectly fills three 6-inch cake tins, and it can also be made a few days in advance. Simply wrap the cooled cakes in clingfilm and refrigerate, or even freeze, them until needed.
- You could, if you wanted, even tint the cake batter with a little of the purple gel food colouring if you’re into that sort of thing.
- There is something intensely satisfying about assembling a three-layer cake. I always put a little dollop of frosting on the cake stand to hold the cake in place and arrange torn pieces of greaseproof paper around the edge so the frosting doesn’t get all over the cake stand.
Recipe Difficulty Levels
Easy
Requires basic cooking skills and ingredients you most likely already have in your kitchen.
Moderate
Requires more experience, preparation and/or cooking time. You may have to source special ingredients.
Challenging
Recipes requiring more advanced skills and experience and maybe some special equipment.
Unicorn Birthday Cake with Candy Bark
Three layers of vanilla buttermilk cake are frosted with purple-tinted white chocolate buttercream and decorated with Midnight Magic Sprinkles. Shards of unicorn candy bark and a purple candy melt drip finish it off perfectly.
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Servings: 12 servings
Calories: 974kcal
Ingredients
for the vanilla buttermilk cake
- 170 grams butter softened
- 450 grams caster sugar
- 5 large free-range egg whites room temperature
- 1 large free-range egg room temperature
- 425 grams plain flour
- 4 tsp baking powder
- 0.5 tsp Shetland sea salt
- 225 ml buttermilk
- 2.5 tsp vanilla extract
for the unicorn candy bark
- 340 grams bright white candy melts
- 75 grams pink candy melts
- 75 grams purple candy melts
- 1 tsp vegetable oil divided
- 2 tbsp Midnight Magic sprinkles
for the white chocolate buttercream frosting
- 150 grams butter softened
- 300 grams icing sugar
- 225 grams white chocolate
- 3 tbsp double cream
- 2-3 drops purple gel food colouring
for the purple drip decoration
- 55 grams purple candy melts
- 1 tbsp double cream
to decorate
- 110 grams Midnight Magic sprinkles (less the 2 tbsp used in the bark)
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Equipment
Instructions
for the vanilla buttermilk cake
- Preheat oven to 350 F/ 180 C/ 160 C fan. Grease and line three 6-inch cake tins with baking paper.
- With a hand mixer, cream together 170 grams butter and 450 grams caster sugar until well incorporated.
- Add 5 large free-range egg whites and 1 large free-range egg and beat until light and fluffy.
- Sift together 425 grams plain flour, 4 tsp baking powder and 0.5 tsp Shetland sea salt in a medium-sized bowl. Combine 2.5 tsp vanilla extract and 225 ml buttermilk in a measuring jug.
- With the hand mixer on low speed, add the flour mixture and buttermilk mixture in alternating increments, mixing until well combined.
- Weigh out the batter and divide by three so each tin is evenly filled. Spoon into the prepared tins and bake in the centre of the oven for 25-35 minutes. Check after 25 minutes and cover with foil if the cake is browning too much.
- Leave the cakes in the tins for ten minutes before removing and cooling completely. If the cakes aren’t needed immediately you can wrap them in clingfilm tightly and keep in the refigerator for up to three days.
for the unicorn candy bark
- Melt 340 grams bright white candy melts, 75 grams pink candy melts, and 75 grams purple candy melts in separate bowls in your microwave, as per the instructions on the packet, or in a heat-proof bowl suspended over a pan of barely simmering water.
- Spread the white candy melts out in a thin layer on a silicone mat or piece of non-stick baking paper.
- Divide 1 tsp vegetable oil between each of the coloured candy melts, if needed to thin, and drop by the spoonful over the top of the white candy melts. Use a chopstick to swirl all the colours together.
- Sprinkle with 2 tbsp Midnight Magic sprinkles, and pop into the fridge to harden. When hardened, carefully cut the bark into shards, and pick a few of the best one to decorate the cake with.
for the white chocolate buttercream frosting
- Cream together 150 grams butter and 300 grams icing sugar.
- Melt 225 grams white chocolate in a heatproof bowl suspended over a pan of barely simmering water. Cool to room temperature.
- Beat the cooled white chocolate and 3 tbsp double cream into the icing sugar mixture.
- Add 2-3 drops purple gel food colouring, and beat well until light and fluffy.
for the purple drip
- Melt 55 grams purple candy melts along with 1 tbsp double cream.
- Cool slightly and pour into a piping bag.
to assemble the unicorn candy bark cake
- Cut the tops of all three cooled cakes off to make them even.
- Place a little spoonful of frosting on the cake stand to hold the cake in place. Peel off the baking paper and place the first cake layer on the stand, cut side up.
- Add a generous layer of buttercream frosting, and top with a second cake, cut side down.
- Repeat with more buttercream and the last cake layer.
- Cover the entire cake, top and sides, with a thin layer of frosting. This is the crumb layer. Chill for 30 minutes.
- Frost the cake with the remaining icing, using a ruler to smooth the top and sides, if desired.
- Decorate the bottom edge of the cake with 110 grams Midnight Magic sprinkles, reserving some for the top of the cake.
- Pipe a purple drip around the top edge of the cake, as pictured, and decorate the top of the cake with the remaining Midnight Magic sprinkles.
- Pick a few of the best shards of unicorn bark to decorate the top of the cake with. Using a sharp knife, carefully cut a slit into the top of the cake to push the candy bark in to so that it stays upright.
- Serve! This cake will keep, refrigerated, for a few days.
Nutrition
Calories: 974kcal | Carbohydrates: 138g | Protein: 8g | Fat: 43g | Saturated Fat: 30g | Cholesterol: 87mg | Sodium: 170mg | Potassium: 320mg | Fiber: 1g | Sugar: 110g | Vitamin A: 800IU | Vitamin C: 0.1mg | Calcium: 149mg | Iron: 1.9mg
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Oven-baked Honey-Sriracha Chicken Wings
wow!!! Looks absolutely stunning! I love the bark and how bright and colourful the cake is, better than a colin the caterpillar that’s for sure!!!
Very Nice Post,
I liked your idea of unicorn cake with candy bark. It looks amazing and perfect for birthday and I liked your cake decoration. Thanks for sharing this great recipe with us. I will try it for my friend’s birthday.
Wow, this is fantastic. Being a full time Children’s Entertainer Unicorn’s are so popular this year so I am always looking for party food/decoration theme ideas to share with my clients and parents on my Facebook page.
I will definitely be sharing this, thank you sooooo much.
Scott
What a cool post! This cake is a work of art, its truly admirable. Thanks for sharing! 🙂
This is absolutely STUNNING! Saving this for next year for either my birthday or my daughter’s, it’s so gorgeous! x
This cake is stunning, I love everything about it. Drama, taste, creativity. Love it!
How pretty is this cake?! I love it. I’m desperate to make some unicorn bark now!!
Katie xoxo
This looks absolutely incredible! I love anything unicorn based especially when it’s cake.
What an amazing looking cake. I LOVE white chocolate so am so pleased you used it for the buttercream. Will be keeping an eye out for the sprinkles now!
Any kid would be lucky to have this awesome cake for their birthday. The color scheme for this is so cool!
Such a creative looking cake. I totally see the Unicorn inspiration and this is such a perfect size!
I wouldnt even attempt to make a cake lol im a dreadful baker unless its a pavlova. This cake looks amazing and you should be super proud of yourself x
Ooo this looks so yummy!! I really want to eat it haha. I love unicorns too! 🙂
It looks like a fun recipe for a cake. Not sure what my daughter would think. She’s not honestly into cakes too much. But this one really does look fun.
Wow that is some serious talent! I love the darkness of the purple drip icing against the light pink that covers the cake. A truly inspired unicorn cake.
This looks amazing! I didn’t think it would be that easy to make a cake like this! Thanks for sharing this beautiful recipe!
I can imagine how amazed the kids were. Lovely photos and detailed steps. Thanks for sharing x
What a beautiful cake! A little different than the typical bright and vibrant cake and I love it!
Wow, this Midnight Magic is one for the best cake I’ve seen for a long time. Very detail step by step and I’m sure this must taste amazing. thx!
Oh my goodness this cake looks absolutely amazing! I would be thrilled to get something like this, but I don’t think I would ever be able make it myself.
this cake looks so good! i wish i could decorate a cake this well. i am totally going to try this cake when i get confident in my cake making abilities!
Not so much into baking but this cake.. oh my, I’d want to bake one and just look at it all day! Sooo pretty! I’m sure it taste heavenly too!
Oh my god, you are an expert! Never will I ever get to bake and make a cake like this. That is a lot of hard work plus passion in one.
this cake is unbelievable in the best way possible. LOVEEEE. I truly adore it. my birthday is next week this might be my cake, just gonna sub it to make it gluten free.
Holy moly this cakes looks amazing! This will certainly get a lot of pins!
Finally something that doesn’t t look like the normal unicorn party ideas !!! Love it !!!!
OMG, this cake is just beautiful! I love it! I can’t wait until I have an occasion to bake a cake; this is definitely I want to try!
Beautiful and creative! Will have yo try this recipe
Such a cool looking cake. I love the purple color of the cake and all the toppings.
This cake looks so yum! Procedure seems easy to make!LOL
What a gorgeous cake!!!! If tastes half as good as it looks it would be a hit! There are an awful lot of little girls out there that would love this!
Oh wow, this cake looks fantastic! The Midnight Magic sprinkles made it even more festive. Amazing shots there, dear!
This cake looks for fun! Love the white chocolate buttercream frosting. sound DELICIOUS! this will make it on the baking list soon! Thanks for all the visual steps.
Oh wow, this is the BEST cake! My daughter would just love it. I’m a huge fan of the color.
Oh my gosh, that is the most AMAZING cake. My children would love it.
I love it!! Purple is my favorite color…I even have some purple tinsel in my hair! Beautiful cake, lovely recipe. I’m going to try this!!
what a pretty cake – love the candy bark and sprinkles (and that you have patience for such a cake)
This is the coolest cake! I don’t know if it would come out very good if I tried to make one, but I may have to anyways!
This cake looks so pretty and bursting with colour. I bet it was so much fun to make x
My children would go bonkers for this, what a beautiful cake! I love the swirly candy bark, so pretty! One to save for future birthday cake inspiration! 🙂
This is one stunning cake and looks so professional! You would definitely be in your children’s good books for making this for a birthday party. The unicorn bark is pretty too!
Oh wow this cake looks amazing. I absolutely love all the colours you have used. I bet they loved it!!
What a beautiful cake Elizabeth. I don’t usually approve of food colourings (unless their real foodstuffs of course), but sometimes it just has to be done and I bet your kids thoroughly approved. I reckon this has more than made up for their shop bought birthday cakes.
I stopped using food colourings years ago too, they give me the heebie-jeebies, but sometimes, I think, it’s ok to step outside the usual and ordinary. I only had this purple on hand because of a recipe commission. It’s ok to have a bit of silly fun. 🙂
What a cake! What a mum for making this cake at a non-birthday too! I can only imagine your children’s faces when they saw it. Love the unicorn candy bark and those sprinkles are really special, I’ll look for some for the next birthday over here (happily that is next year!).
There may have been underlying ‘A very merry unbirthday to you!’ Alice in Wonderland vibes going on with this cake, but they were happy. 🙂