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    Rainbow Unicorn Cake Recipe

    Published: Mar 21, 2021 · Modified: Jun 22, 2021 by Jenn · This post may contain affiliate links.

    Jump to Recipe

    Making a rainbow unicorn cake isn’t as hard as it looks. While this popular cake can be a lot of work, we’re going to take advantage of some shortcuts to help ourselves out. Use this recipe, tutorial, and tips to make a delicious cake for a special occasion.

    Using boxed cake mixes and a unicorn cake topper kit that includes the horn and eyelashes takes away some of the labor-intensive work making this an easy rainbow unicorn cake recipe. These time-savers also eliminate the need to work with fondant or having to place specialty items like edible gold paint in your shopping cart.

    Don’t cheat on the buttercream though. There’s nothing like homemade buttercream frosting for both taste and decorating results.

    completed unicorn rainbow cake unsliced

    Kids will love both the unicorn theme and the special rainbow surprise after the cake is sliced. You can make a rainbow unicorn birthday cake or enjoy it as a sweet treat anytime!

    completed rainbow unicorn cake with two pieces sliced out and resting on plates so you can see the rainbow layers

    Table of contents

    • Rainbow Unicorn Cake Ingredients
    • How to Make a Unicorn Cake
    • Unicorn Rainbow Cake Recipe Notes
    • Cake Decorating FAQs

    Rainbow Unicorn Cake Ingredients

    2 Boxed White Cake Mixes

    Prepared Medium Consistency Vanilla Buttercream Frosting (for decorating)

    Prepared Thin Consistency Vanilla Buttercream Frosting (for icing) – See notes on Wilton Vanilla Buttercream recipe above on thinning your medium consistency recipe

    Gel food colors

    Unicorn Cake Topper Kit

    How to Make a Unicorn Cake

    Prepare cake mix according to box instructions. Be sure to separate the eggs and use only egg whites so the batter will have strong colors giving you a nice rainbow effect.

    Evenly separate the cake mix into four bowls and add electric gel colors. 2-3 drops of different color food coloring per bowl should be enough.

    4 pans and four bowls of cake batter with food coloring in each one of them ready to be mixed

    Lightly grease cake pans and pour batter into prepared pans.

    Bake cakes according to box instructions checking at the 15-minute mark.

    Remove from oven and allow to cool at room temperature until the cakes are cool enough to be wrapped in plastic wrap and placed in the freezer.

    Make your buttercream with an electric mixer while the cakes cool in the freezer. I use Wilton’s classic recipe and my stand mixer with whisk attachment to make the best buttercream frosting for all my cakes.

    Crumb coat the cake with a thin layer of white frosting making sure to put the buttercream in between each layer as you build a cake. The easiest way to do this is directly on the base of a cake stand or on a disposable cake board.

    Once the whole cake is frosted, prepare your colored icing and put it into piping bags with star tips. A medium-stiff consistency icing is going to be required to create the unicorn mane roses on top of the unicorn’s head.

    Remove the unicorn horn/unicorn ears cake topper from its package and center it at the top of the cake.

    After placing the unicorn horn topper on top of the cake, place the unicorn eyes as symmetrical as possible on the front of the cake. Just eyeball it! *wink*

    crumb coated unicorn cake with topper and eyelashes added. yellow, red, and teal icings are in frosting bags in the foreground

    Use different shape/size star tips to create the roses and border as you like. See the photo below. This is where a coupler comes in handy.

    Unicorn Rainbow Cake Recipe Notes

    • Because these are 1-inch rainbow 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 a toothpick in it and it comes out clean.
    • 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.
    • While using a coupler is not necessary for this particular activity it will be helpful to change the tips out.
    • A medium-stiff consistency icing is going to be required to create the roses on top of the unicorn’s head.
    • Make sure you hold your piping bag at a 45° angle. Apply even pressure when squeezing out the icing. Stop squeezing and then pull the tip away.

    Cake Decorating FAQs

    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.

    How do I transfer the cake to a cake stand?

    Stack the layers of cake onto a cake board and decorate it completely. Then, transfer the cake, board and all, to the cake stand.

    Rainbow Unicorn Cake Recipe

    Jenn
    Making a rainbow unicorn cake isn't as hard as it looks. Use this recipe, tutorial, and tips to make a magical cake for a special occasion.
    5 from 1 vote
    Print Recipe Pin Recipe
    Prep Time 25 mins
    Cook Time 15 mins
    Additional Time 2 hrs
    Total Time 2 hrs 40 mins
    Course Desserts
    Cuisine American
    Servings 1 Cake
    Calories 203 kcal

    Equipment

    • Kasmoire Piping Bags and Tips Set,24pcs Cake Decorating Tools with 6pcs 3 Sizes (12”+14”+16”) Reusable Icing Pastry Bags, 6 Different Icing Bags Tips, 6 Piping Bags Couplers and 6 Frosting Bags Ties
    • Unicorn Cake Topper with Eyelashes Party Cake Decoration 
    • AmeriColor Food Coloring – Electric Kit – Soft Gel Paste, 7 .75 Ounce Bottles
    • Wilton Easy Layers Round Layer Cake Pans Set, 4-Piece

    Ingredients
      

    • 2 White Boxed cake mix prepared according to box instructions
    • Gel food coloring
    • Buttercream icing

    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.
    • Import prepared batter into pans.
    • 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 a toothpick in it and it comes out clean.
    • Remove the cakes from the oven and allow them to cool at room temperature until the cakes can be wrapped in plastic wrap and placed 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.)
    • Make buttercream icing.
    • Crumb coat the cake with a thin layer of vanilla buttercream making sure to put the buttercream in between each layer as you build the cake.
    • Allow the cake time to rest before moving on to the next step. (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 it into piping bags with star tips. (While using a coupler is not necessary for this particular activity it will be helpful to change the tips out.) A medium-stiff consistency icing is going to be required to create the roses on top of the unicorns head
    • Remove the unicorn horn cake topper from its package and center it 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.
    • Using a star tip, create roses on top of the cake and around the base.

    Notes

    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
    Keyword birthday cake, dessert recipes, rainbow unicorn cake, unicorn rainbow cake
    Nutrition Facts
    Rainbow Unicorn Cake Recipe
    Amount Per Serving (1 serving)
    Calories 203 Calories from Fat 18
    % Daily Value*
    Fat 2g3%
    Saturated Fat 1g6%
    Polyunsaturated Fat 1g
    Cholesterol 1mg0%
    Sodium 382mg17%
    Carbohydrates 44g15%
    Fiber 1g4%
    Sugar 24g27%
    Protein 2g4%
    * Percent Daily Values are based on a 2000 calorie diet.
    Did You Make This Recipe?Please leave a comment below or share on Pinterest

    Enjoy your beautiful rainbow unicorn cake!

    You might also like…

    Unicorn Popcorn Recipe

    Unicorn Muddy Muddies Recipe

    Unicorn Donuts

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    Hi, I'm Jenn, a Southern food blogger and mother living in Alabama. After having my wonderful daughter, I decided to embark on a journey of sharing my Southern cooking recipes with the world.

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