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Rainbow Unicorn Cake

A delightfully easy Rainbow Unicorn Cake that will charm all unicorn AND rainbow lovers. This rainbow birthday cake bursts with color from the inside out. To decorate just add the unicorn topper and eyelashes and VOILA – couldn’t be easier!

rainbow unicorn cake long pin image

I was curious to find out what a unicorn symbolizes so I looked it up. The unicorn symbolizes grace, beauty, and love.

These three attributes are all things you will add to this Rainbow Unicorn Cake as you prepare it for a family birthday, kids party, or any family gathering!

I’m sure you have a unicorn lover in your house or know someone who is (don’t we all?). And I’m definitely sure we ALL love rainbows. Put those two things together, and you will no doubt have something magical.

Your cake will most certainly be magical (just like these Rainbow Unicorn Cupcakes!) when you put your own spin on the cake and frosting colors!

Love rainbows and magical recipes? Check out The BEST Easy Colorful Rainbow donuts and How To Make Rainbow Jello Squares!

Rainbow unicorn cake with a cut slice on a plate

Ingredients Needed for Rainbow Birthday Cake

  • White Boxed Cake Mix – you can definitely make your own cake from scratch if that is your preference.
  • Buttercream Icing – making your own is always an option but there are some great (time-saving) store-bought options you can use as well.
  • Food coloring

Tools Needed

  • Layered cake pan set
  • Unicorn cake topper
  • Unicorn Sprinklefetti
  • Cake drum

Unicorn Cake Video

See it in action! Here’s a short video showing the process of making this fun, beautiful cake!

How to Make a Rainbow Unicorn Cake

Just in case you can’t watch the video, here are the steps for making this cake. The process of making this Unicorn Cake is not difficult at all. There are some helpful notes down below.

Step 1

First, you will prepare both cake mixes according to the directions on the box. Divide the batter into four separate bowls.

Step 2

Add the food coloring in each of the bowls of batter (each bowl will be a different color) and mix well.

coloring the different cake layers

Step 3

Once you have the cake pan prepped, you can pour the colored batter into each pan and bake.

Step 4

Now that the cakes are done, out of the oven, and cooled sufficiently, you are ready to start decorating!

Crumb coat the cake, making sure to put a thin layer of buttercream in between each layer as you build your cake. Also frost the outside of the entire cake.

Make sure the iced cake has time to rest and set before decorating.

putting the layers of rainbow cake together

Step 5

Now comes the REALLY fun part…..decorating. Prepare your icing with colors of your choice. Put the icing in the piping bag and have FUN! A star tip and piping bag works best for this step.

decorating the unicorn cake collage image

Step 6

Last but not least, place the unicorn cake topper on the top of the cake and put the eyelashes on the front of the cake.

And that is all there is to making a layered rainbow unicorn cake! Great job!

unicorn cake decorating final collage image

Recipe Notes and Tips

  • Begin to check the doneness of the cake at the 15-minute mark as these are 1-inch cake layers and they will probably cook faster than the box tells you.
  • If you’re in a hurry to cool your Rainbow Unicorn Cake layers, chill them in the fridge for at least 2 hours before starting the decorating process.
  • If you are using store-bought buttercream icing, try whipping the icing to help incorporate air. That will make it easier to spread and pipe onto the cake.
  • Hold your piping bag at a 45° angle. Apply even pressure when squeezing out the icing. Stop squeezing and then pull your tip away.
slices of rainbow layered cake from above

Rainbow Unicorn Cake Variations to Try

There are a few fun ways you can change up this cake to make it unique!

Try different colors of food coloring…..bright colors, pastel colors, or variations of the same color such as four different shades of pink.

Another fun twist could be different flavored cake mixes. Each layer could be a different flavor such as strawberry, lemon, carrot… get the idea. Funfetti cakes mixes would be darling…just sayin’! 😉

You could also use flavored extracts to add to a vanilla cake for a delicious change-up.

rainbow birthday cake with cut slices


Given the steps involved with making a layered cake like this Rainbow Unicorn Cake, there are sure to be questions. Here are some common ones…if I missed one you have, please ask it in the comments below!

What can I use if I don’t have a piping bag?

If you do not have a piping bag, a sandwich bag will work. A sandwich bag is not as thick and sturdy as a piping bag, so it may feel flimsy. But it will work.

And you will still need a piping tip to achieve the desired look for your rainbow unicorn cake.

Why do we use couplers when decorating?

A coupler will allow you to change the decorating tip while using the same colored icing which will allow you to change designs while keeping the same consistency in the icing.

Can I use plastic decorating tips?

Yes! Keep in mind that you will not be able to change out the tips while decorating with plastic tips. Plastic tips will retain more grease where metal tips will not.

What is the best way to clean piping tips?

I would suggest soaking them in hot, soapy water for a bit to loosen any clumpy, dried-on icing and remove any grease.

If they’re dishwasher safe, rinse well and put them in the dishwasher in a lidded basket or mesh bag designed for use in a dishwasher.

If they aren’t dishwasher safe, rinse them after soaking and possibly soak again before rinsing and setting the tips out on a towel to dry.

unicorn birthday cake with a cut slice

More Rainbow Recipes to Try

Everyone loves rainbows! If you love this Rainbow Unicorn Cake recipe, check out some more of our fun rainbow recipes and activities.

  • Rainbow Jello Squares
  • Rainbow Unicorn Cupcakes
  • Easy Colorful Rainbow Donuts
  • Rainbow Walking Water Experiment

Pin For Later!

rainbow birthday cake pin image
Rainbow Unicorn Cake

Rainbow Unicorn Cake

A beautifully colored and layered rainbow cake that's SUPER easy to make and decorated as a unicorn.


  • 2 white boxed cake mixes
  • Buttercream icing
  • Food coloring


  1. Prepare the cake mixes according to the directions on package.
  2. Separate the cake mix batter equally into 4 bowls.
  3. Use 1 - 2 drops of food coloring in each bowl for desired color. Mix well.
  4. Lightly grease 4 cake pans.
  5. Pour 1 color of each batter into each of the 4 pans.
  6. Bake according to direction on the cake mix box.

Assembling the cake

  1. Prepare your buttercream frosting.
  2. Crumb coat the cake using a thin layer of buttercream. Be sure to put the buttercream in between each layer as you stack the cake.
  3. Allow approximately 15 minutes for the cake to rest after crumb coating. The buttercream will need a little time to set up until no longer wet.
  4. Prepare the frosting in the colors of your choice. Put icing into piping bags using star tips.
  5. Place a unicorn horn cake topper on the top center of the cake.
  6. Next, place eyelashes on the front of the cake.


    As you are baking the cakes, keep in mind that the layers will be about 1 inch thick and may cook faster than instructions on the box. Check the doneness of the cake approximately 15 minutes into the cooking process.

    The cool the cakes quicker, refrigerate for 2 hours before crumb coating and assembling. Freezing the cakes is encouraged if you have time as this will allow easier assembly.

    A star tip is used to create the roses on the top of the unicorns head. The icing should be a medium stiff consistency to create the roses with the best outcome.

The post Rainbow Unicorn Cake appeared first on Made In A Pinch.

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Rainbow Unicorn Cake


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