Kids’ Birthday Party Ideas: Mystical Unicorn Cake

If you follow me on Instagram or Facebook, you may already know I made this Mystical Unicorn Cake for my daughter’s birthday which was a “Rainbows and Unicorns” themed party. I posted it on Social Media just after I had finished  decorating it. When she got home from school she was shocked and amazed. To say the least, she big puffy heart L-O-V-E-D this cake and I can’t blame her. I love it, too. 


Finished Mystical Rainbow Unicorn cake. #Kids #Birthday #Party #Ideas


I want to start by saying I’m not a professional cake baker or decorator – yes, I know the cake has some ovbious imperfections you would not see from a professional bakery. But I still feel like if I can tackle this cake, you can, too!

Michael’s Crafts says this is an advanced level cake, and that’s probably true with the way they decorated their unicorn’s mane using different tips and flower shapes. However, I used only a single 1M cupcake piping tip for the entire project.

I embellished the flower mane with Sixlets chocolate candies (Sixlets are round, candy-coated chocolate balls) from the candy buffet but you could use whatever candy you have on hand – or none at all. I also had purchased some decorator sprinkles in the shape of the number 8 – which I have enough left over to share with a friend – maybe two.

You can use whatever candy or edible or candy embellishments you prefer – or none at all. It’s totally up to you. The total cost of this cake was about $20 – $25 plus my time. Similar cakes at my local bakery are about $80+. To make this cake as outlined in the Wilton instructions on Michael’s site, you could easily spend upwards of $80 or more.

I used just regular liquid food coloring [paid link] and not the Wilton gel coloring [paid link]  typical of cake making. If you don’t have gel cake colorings in your pantry, go with your regular liquid food coloring [paid link] like you’d use to dye Easter eggs. It works very well.


The back of the Mystical Rainbow Unicorn cake.


The total time it took me to make this cake start to finish was about 4 hours. That includes baking the cakes, stacking and frosting the cakes, and then adding the flower mane and other embellishments. I broke this up over two days. I baked the cakes one day afternoon and then stacked and frosted the cake the following day (one day before the party).

I want to also note that I only have 1 (1M) piping tip, so this meant cleaning the tip after each bag of frosting and then filling the next frosting bag. Doing this definitely added on some extra time onto the total project time. Also, the cake inside is rainbow colored which also meant extra time creating the color shades for each batch of cake batter.

Finally, I was working with only one (1) 8-inch wedding cake syle pan which meant it took some extra time to get all four (4) layers baked – I did not factor that extra time into the four hours as it was inactive time.

Fondant ears and lillipop horn for mystical unicorn cake.


I broke the overall project time into smaller time increments so I didn’t feel rushed or overwhelmed with the project. This really helped me out a lot. I figured that worst that could happen was that I would end up with some very expensive cupcakes if the project failed. Overall, I was very pleased with how the cake turned out and I received all my time and energy back 10-fold in warm-fuzzy feelings for how much my daughter loved her cake. 

The unicorn’s ears are made from white fondant that I purchased at Walmart. They sell small 8-ounce tubs of it by the cake mixes and decorating sprinkles of the grocery store. It was about $3.69 and was the perfect size for this project. Larger boxes retail for about $20 and would be a waste for me since I have never worked with it before.


Making the ears for the mystical Unicorn cake.

I first broke off about 2-ounces of the fondant (1/4 of the pack) and shaped it into two walnut-sized balls. I then used my thumb as the center well of the ear and shaped it around to form the outer ear. I then inserted a toothpick into the ear (optional) and set it aside to dry for 24-hours. I then “painted” the insides of the ears gold using a mixture of almond extract and edible gold glitter I had on hand. You could also paint the insides with a mixture of almond extract with a drop of red or yellow food coloring and allow it to dry.


The candy buffet of the kids birthday party


As a side note: The unicorn horn can also be made from the rest of the fondant but I had already purchased the giant swirl lollipop to use as the horn so I re-wrapped the remainder of the fondant and will use it for another project.


my daughter and her unicorn cake


My daughter was so smitten with this cake that she didn’t even notice the design flaws. My point being, your child will love the cake you decorate no matter how it turns out – perfect or not. They understand the love that goes into making the cake of their dreams.

I know my daughter was proud both of me and her birthday cake. I could hear it in her voice whenever she said “My Mom made this cake! Isn’t it so pretty.” I could feel the words in my heart, too. It was very much worth the time that went into making this cake.


my daughter and her mystical unicorn cake.


Another thing the kids loved about this cake was the rainbow they found inside when we sliced it open. It really was magical. Creating the rainbow effect was pretty simple just by dividing the batter into 6 small bowls and then tinting the batter.

making the colored batter for the mystical unicorn cake.


You can really do any color shades you like – for example an Ombre effect or pastels, for example.

Rainbow cake batter in the pan.


Below is a photo of the cake sliced – it’s just a picture I took mid-party after my Aunt Jane texted and asked to see the center of the cake. I promised myself I would take a better photo for the blog but never got the chance while catering to all the kids at the party. So, I apologize for that.

It can be hard to imagine, but when you slice the cake from the outside edge to the center, each layer has it’s own perfect rainbow. The kids all loved it.


the center of the mystical unicorn rainbow cake.


You can easily create a rainbow of colors from the standard (primary color) 4-pack of McCormick Liquid Food Coloring [paid link]. I added the colorings to the bowls in drops or sets of drops until I got the color I wanted. For non-primary colors, I used the following recipe:

Orange, for example, is 1 drop of orange with 2 drops of yellow. To deepen the shade, I would add 1 drop of orange with 2 drops of yellow again or to get a lighter shade, I would add another drop of yellow or darken with another drop of red.

The most difficult color to achieve for me was purple. I did start the purple frosting over in a small batch – I knew if I did not get the shade I envisioned that I would be displeased with the whole cake.

color chart for rainbow cake batter and frosting.

To save myself the disappointment, I started the violet frosting over again and I am glad I did. I ended up with a very pretty shade of violet.


Save this Mystical Unicorn Cake to your  “Kids” and/or “Desserts” Pinterest board!

And while we’re at it – let’s be friends on Pinterest! I’m always pinning tasty new recipes!

Make your next party magical with this Mystical Rainbow Unicorn cake. #Kids #Birthday #Party #Ideas
Make your next party magical with this Mystical Rainbow Unicorn cake. #Kids #Birthday #Party #Ideas


Looking for other kids’ party ideas? Check out there Little Mermaid Oreo Pops!

Make your next party magical with this Mystical Rainbow Unicorn cake. #Kids #Birthday #Party #Ideas

Mystical Unicorn Cake

Ronda Eagle | Kitchen Dreaming
Make your next party magical with this Mystical Rainbow Unicorn cake. #Kids #Birthday #Party #Ideas
5 from 6 votes
Prep Time 3 hours
Cook Time 25 minutes
Total Time 3 hours 25 minutes
Course Dessert
Cuisine American
Servings 24 servings
Calories 819 kcal


  • 2 boxes White Cake Mix [See Note 1]
  • 2 ½ cups water , divided (1 ¼ cups per each box)
  • 2/3 cup vegetable oil , divided (1/3 cup per each box)
  • 6 large egg whites (3 egg white per each box) [See Note 2]
  • 2 teaspoons pure vanilla extract ( 1 tsp per each box)
  • 1 teaspoon almond extract , divided (1/2 tsp per each box)
  • Food Coloring (4-Pack), Primary Colors

Frosting for the outer cake and between the 4 layers (4 cups):

  • 1 cup vegetable shortening (Crisco) solid.
  • 1 cup butter , softened
  • 2 teaspoons clear vanilla extract [paid link] [See Note 3]
  • 8 cups confectioners' sugar (approximately 2 lbs.) sifted.
  • 4 tablespoons milk

Frosting for the Mane flowers (4 cups):

  • 1 cup vegetable shortening (Crisco) solid.
  • 1 cup butter softened
  • 2 teaspoon clear vanilla extract [paid link] [see note 3]
  • 8 cups confectioners' sugar (approximately 2 lbs.) sifted.
  • 4 tablespoons milk.

Special Equiptment:

  • Tip 1M with coupler
  • 7 disposable decorating bags
  • 4 - 8 " Round Cake Pans
  • Offset spatula , optional


  • Preheat oven to 350ºF. Grease and line two 8-inch round cake pans. [See Note 4]
  • In a medium bowl, whisk [paid link] together 1 box of cake mix, 1-¼ cups water, 1/3 cup vegetable oil, and 3 egg whites. For a pure white cake batter to be tinted, do not use the egg yolks.
  • Mix vigorously by hand or on the medium speed of an electric mixer for 2 minutes.

For Rainbow cake: Divide the batter evenly between 6 bowls (about ½ cups each bowl). Then color each of the batters using the following recipe:

  • Red – 15 drops of red
  • Orange – 5 drops of yellow and 2 drops of red
  • Yellow – 8 drops of yellow
  • Green – 9 drops yellow plus 2 drops of blue ( or 11 drops of green)
  • Blue – 14 drops of blue
  • Purple – 7 drops red plus 2 drops of blue
  • Next, layer the cake batter evenly into the prepared cake pans one color at a time starting with red. Pour ¼ cup of batter into the center of the pan and allow it to gradually spread into a circle on its own. Do not touch the batter once it is in the pan.
  • Next, pour ¼ cup of batter into the center of the pan on top of the red batter.
  • Continue with the rest of the batter colors: yellow, green, blue, and purple. Remembering to allow each color to spread evenly on its own. Level the pan by gently shaking the pan.
  • Bake for 30 to 35 minutes or until a cake tester inserted in the center comes out clean. Allow to cool for 5 minutes before inverting cake onto a wire rack. Cool completely.
  • Repeat steps 1-8 with the second cake mix. [See Note 5]
  • Once cakes have cooled completely, level them with a cake leveler or serrated knife. Having level cakes free of the rounded “dome” tops is essential for cake stability and construction.
  • Prepare the cake frosting by first creaming the butter and shortening together in a large mixing bowl [paid link]. Then in stages, add in the powdered sugar, and vanilla. Add the milk 1 tablespoon at a time until you get a stiff but spreadable frosting. A frosting too thin will not be able to pipe flowers in the second batch.
  • Stack first of the cakes tiers on a 9-inch cake board or cake stand. Fill a large pastry bag with white frosting. Pipe rings around the inside edge of the cake layer and then fill in the circle with more frosting. Then smooth the frosting out evenly with a knife. Carefully add the next layer so that it is center. Once the second layer is center, press the cake firmly down with the palms of your hands being careful not to break the layer. Then again pipe in the frosting and spread it evenly with a knife. Repeat this process two more times until all 4-cakes are frosted and stacked.
  • Next, put a really thin coating of white frosting over the entire cake. It doesn’t have to look neat or finished. This is the “crumb layer”. It locks the stray crumbs into frosting so they do not end out on the outside of the finished cake. [See Note 6]
  • Once the crumb layer is on, refrigerate for 25 minutes, if possible. I do this to lock down the crumb layer before I start with the finished frosting layer.
  • With a piping bag filled with white frosting, pipe circles of frosting over the outside of the cake and over the top. This is easiest with a turntable but can be done by gently moving the cake stand.
  • Running the knife under hot water and wiping with a paper towel between uses helps make the frosting really smooth. Remove excess frosting back into the mixing bowl [paid link].
  • For an 8-inch, 4-layer cake, you will use all or nearly all the first batch of pure white frosting.

Piping the Mane:

  • Prepare the second batch of frosting the same at the cake frosting following step 11.
  • Divide the frosting evenly between 6 bowls (about 2/3 cups each).
  • Prepare the frosting colors as directed in sub-step 4.
  • With a toothpick I made a small arrow in the top of my cake to mark the front center if the cake (it later was piped over with swirls and flowers. Using that mark I created, I “eye-balled” the placement of the flowers, how they would fall over the back side of the cake and flow along the side along to end at the front center of the bottom of the cake.
  • Starting with red, I piped about 8 – 10 “rosette” swirls starting a little off center and then in a few inch increments along the imaginary line I had to how the main would fall. I repeated this cleaning the tip between colors and then, with the same 1M tip, pipe small star shaped flowers as needed to fill in any gaps. Repeat this with the remaining colors.
  • Pipe eyes onto the front center of the cake. Place horn on the top center of the cake and the ears on either side of the horn.
  • Enjoy the rewards of all your hard work - the kids will LOVE it!


  1. White cake mix yields the best results as compared to a standard yellow cake mix.
  2. Use egg whites only (no yolks) for best results. Do not use egg beaters or other boxed egg whites - they are not recommended for baking.
  3. Clear baking vanilla is best to keep the cake mix as white as possible, but regular vanilla may be substituted.
  4. I used 1 cake pan four (4) separate times, if you have 2 or 4 8-inch pans you can always bake all 4 layers at once. I oiled the pan with non-stick cooking spray and then lined it with a round parchment paper [paid link] disc. I then also sprayed the parchment with non-stick cooking spray to prevent the cakes from sticking to the pan.
  5. I prepared each cake mix separately. Some cake mixes do not do well when doubled.
  6. The crumb layer is a very thin layer, you can usually still see through it. It's only purpose is to lock in any cake crumbs so they do not get onto the outside layer of the cake.


Serving: 1sliceCalories: 819kcalCarbohydrates: 115gProtein: 3gFat: 40gSaturated Fat: 20gCholesterol: 41mgSodium: 453mgPotassium: 51mgFiber: 1gSugar: 97gVitamin A: 481IUVitamin D: 1µgVitamin E: 2mgVitamin K: 13µgCalcium: 106mgFolate: 31µgIron: 1mgZinc: 1mg
Tried this recipe?Let us know how it was!

8 thoughts on “Kids’ Birthday Party Ideas: Mystical Unicorn Cake”

  1. I wanted to make a special cake for my granddaughter who loves unicorns. I’m not a pro but also not a novice baker so I thought I’d give it a try. It turned out wonderful and she was so surprised that Nana could make such a cake. Thanks for making her birthday so special!

  2. You made it look so easy I gave it a try! It was a total success – the kids absolutely loved it. thanks for giving me the confidence to try this cake. It looked so hard but really it wasn’t!

  3. The cake was really moist and the kids loved the rainbow in the layers. So perfect and I loved the unicorn mane you made it much easier than other posts I’ve seen.


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