Learn how to make a stunning and whimsical rainbow unicorn cake with our delightful recipe. Bring a touch of magic to your next celebration with this show-stopping cake that combines rainbow layers with the enchanting charm of unicorns.

A Rainbow Unicorn Cake is a popular cake that is not only looks magical, but tastes delicious too!

A unicorn rainbow cake features layers of cake that are moist and tender cake layers with a rainbow effect, symbolizing the vibrant and joyful spirit of unicorns. All topped off with a creamy buttercream frosting.

This easy rainbow unicorn cake is a true showstopper, featuring layers of colorful cake, creamy frosting and whimsical unicorn decorations.

Whether you’re celebrating a unicorn themed birthday party, a baby shower, or simply want to bring a sweet treat to special occasions, a beautiful rainbow unicorn cake is the perfect choice.

The process of making this cake allows you to tap into your creativity, as you mix and match colors, experiment with different decorating techniques, and bring your unicorn cake to life.

How To Make A Unicorn Cake

*Watch the video tutorial for step-by-step directions.

Ingredients

2 White Boxed cake mix, prepared according to box instructions, colored and baked.
Buttercream Frosting

Directions

The first step is to make your layer cakes. Prepare box cake mix according to the box’s recipe instructions in a large bowl.

Pour batter into four different bowls using the electric gel food colouring to make each a different color. 1 to 2 drops of coloring will be enough for a bright rainbow cake color.

Lightly grease 8-inch cake pans and line the bottom of the pans with parchment paper. Pour the cake batter into your prepared pans.

Bake cakes according to box instructions.

Because these are 1 inch cake layers, which are different sizes then what the box says, they may cook faster. Begin to check them at the 15 minute mark. Cakes are done when you stick in a toothpick in it and it comes out clean.

Remove from oven and cool cake at room temperature until the cakes can be wrapped in plastic wrap in the freezer.

While freezing the cakes is not necessary it is strongly encouraged as it will make the icing of the cake easier when it’s time to assemble. If you are in a rush chill the cakes in the fridge for at least two hours before attempting to assemble the cakes or else the cakes can come apart when you are icing them.

Next comes the fun part – decorating the cake! Whip up a batch of smooth and creamy buttercream frosting.

Place your first layer on a cake board, apply a thin layer of frosting and then add the second layer. Continue with each cake layer to hold them together.

Frost the whole cake with a crumb coat to seal in the moisture and create a smooth surface.

Allow the cake time to rest before moving on to the next step. The buttercream icing will crust over meaning when you touch it with your finger after about 15 minutes the Icing is no longer wet.

Prepare your colored frosting and put into piping bags with star tips. While using a color is not necessary for this particular activity it will be helpful to change the tips out.

Make sure you hold your piping bag at a 45° angle. Apply even pressure when squeezing out the icing. Stop squeezing and then pull your tip away.

Remove the unicorn cake topper from its package and center on the top layer of cake, along with the unicorn ears.

After placing the unicorn horn topper on top of the cake select your unicorn’s black eyes and place them on the front of the cake, as symmetrical as possible. The best thing to do this may be with a pair of tweezers.

A medium stiff consistency icing and a star tip is going to be required to create the roses on the top layer of the cake, which will be the unicorn mane.

Relevant Recipes

How to Store Your Unicorn Cake

Store your cake in the refrigerator until you are ready to display your unicorn cake on a cake stand. You may need to adjust your refrigerator’s shelves to help the cake fit.

If you want to make your cake layers in advance you can! After they completely cool, wrap each cake layer in plastic wrap and then aluminum foil. You can freeze your unicorn cake layers for up to 3 months. When you are ready to thaw out your layers, start out in the refrigerator overnight and then let them come up to room temperature.

Unicorn Cake Tips and Tricks

Use gel food coloring to achieve vibrant and distinct rainbow colors. Start with a small amount of coloring and gradually add more until you reach the desired intensity.
To achieve evenly baked cake layers, ensure your oven is preheated to the correct temperature.
For smooth and seamless frosting, ensure your buttercream is at the right consistency. If it’s too stiff, add a splash of milk or cream. If it’s too runny, add more powdered sugar. Aim for a spreadable yet firm consistency.
Let your creativity shine when it comes to decorating the unicorn features. Use a variety of edible decorations like white fondant, edible glitter, edible gold paint and colorful sprinkles to bring the unicorn to life. Don’t be afraid to experiment and have fun with the design!
Once your cake is assembled and decorated, place it in the refrigerator to chill for at least 30 minutes. This helps the frosting to set and creates clean and sharp edges when slicing.

Unicorn Rainbow Cake FAQ’s

What do I do if I don’t have a piping bag?

While I strongly encourage you to purchase piping bags, you may use a small sandwich bag but it will require you to have a piping tip.

Can I use plastic tips?

Yes you can use the plastic decorating tips. However you will not be able to change out the tips while you’re decorating.

Why do we use couplers when decorating?

The couplers make it easy for you to change the piping tip while still using the same color.

What’s the best way to clean the piping tips?

Boil them in hot water and allow them to air dry.

What tips to use for unicorn cake?

For a unicorn cake, you can use a variety of piping tips to create different textures and designs. Here are some popular piping tips that work well for decorating a unicorn cake:
Round tip (such as Wilton #12 or #10): This tip is great for piping smooth lines, dots, or creating small details like eyes or nostrils.
Star tip (such as Wilton #18 or #21): Use this tip to create textured fur or hair on the unicorn’s mane or tail. You can also pipe rosettes or stars to add dimension to the cake.
Open star tip (such as Wilton #1M or #4B): This tip is perfect for creating swirls, ruffles, or large star-shaped decorations. You can use it to pipe the unicorn’s mane or create a border around the cake.
Petal tip (such as Wilton #104 or #125): This tip is ideal for creating delicate flower petals or ruffled effects. You can use it to pipe flowers or to create the unicorn’s ears.
Leaf tip (such as Wilton #352 or #366): Use this tip to pipe leaves, feathers, or scales for decorating the unicorn’s body or adding foliage around the cake.
Remember to practice piping techniques before decorating your unicorn cake and have fun experimenting with different designs and patterns.

How high should a unicorn cake be?

A typical unicorn cake is often made with three to four cake layers, each measuring about 2 inches in height. This would result in a total cake height of approximately 6 to 8 inches, excluding any additional decorations like the unicorn’s horn or ears.

How to Make a Unicorn Cake

Yield: 1 cake

Prep Time: 10 minutes

Cook Time: 15 minutes

Additional Time: 2 hours 30 minutes

Total Time: 2 hours 55 minutes

This easy Unicorn Cake in beautiful rainbow colors is perfect for your next birthday party! This step by step guide will show you how to make the entire cake from start to finish.

Ingredients

2 White Boxed cake mix
Buttercream icing
Unicorn sprinkles mix
Unicorn cake topper
Electric Gel Colors

Instructions

Prepare cake mix according to box instructions.
Separate the cake mix into four bowls using electric gel colors 1 to 2 drops of coloring will be enough for a favorite cake color.
Lightly grease cake pans and line bottom of the pan with parchment paper.
Pour batter into pans and bake according to box instructions.
Because these are 1 inch cake layers they may cook faster than your box tells you. Begin to check them at the 15 minute mark.
Cakes are done when you stick in a toothpick in it and it comes out clean.
Remove from oven and allow to cool at room temperature until the cakes can be wrapped in plastic wrap in the freezer.
Make your buttercream.
Crumb coat the cake with a thin layer of vanilla buttercream making sure to put the buttercream in between each layer as you build a cake.
Allow the cake time to rest before moving on to the next step. The buttercream will crust over, meaning when you touch it with your finger after about 15 minutes the Icing is no longer wet.
Prepare your colored frosting and put into piping bags with star tips. While using a color is not necessary for this particular activity it will be helpful to change the tips out.
Remove the unicorn horn cake topper and the ears from its package and center at the top of the cake.
After placing the unicorn horn topper on top of the cake select your eyelashes and placing them as symmetrical as possible.
A medium stiff consistency icing is going to be required to create the roses on top of the unicorns head using a star tip we will be able to create roses on top of the cake.

Notes

How to Store Your Unicorn Cake

Store your cake in the refrigerator until you are ready to display your beautiful rainbow unicorn cake on a cake stand. You may need to adjust your refrigerator's shelves to help the cake fit.