Estimated reading time: 7 minutes
This Unicorn Rainbow Cake is perfect for birthdays, baby showers, or any special occasion. It’s made with 5 rainbow color layers of delicious, moist, vanilla cake and covered in pastel color, buttercream frosting, decorated with sprinkles and candy pearls. The unicorn horn cake topper and cute eyes with eyelashes on the front complete this show-stopping unicorn cake character.
Table of contents
Unicorn Rainbow Cake
Hi Everyone, for my daughter’s 5th birthday, she requested a Unicorn Rainbow Cake.
She was very specific about the type of cake and the colors, so I knew I had to get this cake right.
I’m sharing with you the recipe and everything needed to bring this Unicorn Rainbow Cake together, so you can make one too right at home!
Ingredients
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WHITE CAKE BATTER
- 4 large egg whites (room temperature)
- 2 cups all-purpose flour (or the same amount of cake flour)
- 1 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon Kosher salt
- 1/2 cup unsalted butter
- 1 3/4 cups granulated white sugar
- 1 teaspoon pure vanilla extract
- 1 1/3 cups buttermilk
- 5 colors of gel food coloring (I use purple, green, yellow, orange, and red)
BUTTERCREAM
- 1/2 stick of unsalted butter
- 1 teaspoon pure vanilla extract
- 4 cups confectioner’s sugar
- 1/2 cup whole milk
TOPPINGS
Kitchen Tools
- measuring spoons and cups
- mixing bowls
- stand mixer and/or handheld electric mixer
- cake stand
- cake decorating tips, Russian tips
- cake spatula for serving
- baking spatula(s)
- a cake carrier for storage (I use one made by Wilton), optional
Web Story
If you make this Unicorn Rainbow Cake and like it, please give the recipe a rating in the recipe card below and let us know what occasion you made it for in the comments below.
Thank you for reading and following along!
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Unicorn Rainbow Cake
This Unicorn Rainbow Cake is perfect for birthdays, baby showers, or any special occasion. It’s made with 5 rainbow color layers of delicious, moist, vanilla cake and covered in pastel-color, buttercream frosting, decorated with sprinkles and candy pearls. The unicorn horn cake topper and cute eyes with eyelashes on the front complete this show-stopping unicorn cake character.
Ingredients
White Cake Batter
- 4 large egg whites (room temperature)
- 2 cups all-purpose flour (or the same amount cake flour)
- 1 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon Kosher salt
- 1/2 cup unsalted butter
- 1 3/4 cups granulated white sugar
- 1 teaspoon pure vanilla extract
- 1 1/3 cups buttermilk
- 5 colors of gel food coloring (I use purple, green, yellow, orange and red)
Buttercream
- 1/2 stick unsalted butter
- 1 teaspoon pure vanilla extract
- 4 cups confectioner's sugar
- 1/2 cup whole milk
Toppings
Instructions
White Cake Batter
- Grease the 5 round cake pans and set them aside.
- In a large mixing bowl, combine the all-purpose flour, baking powder, baking soda, and Kosher salt. Set aside.
- Preheat the oven to 325 degrees F.
- In a large mixing bowl, beat butter with a handheld electric mixer for about 30 seconds. Add the granulated white sugar and 1 teaspoon of pure vanilla extract. Beat until combined. Add the egg whites gradually, one at a time beat well after adding each one.
- Add the flour mixture and buttermilk alternately to the butter mixture gradually. Mixing well after each addition. Add the butter evenly to each of the 5 baking pans.
- Add drops of the gel food coloring to the 5 cake pans and gently stir to combine. (Alternately, you can mix the colors in separate bowls if you don't want to mix them in the cake pans.)
- Bake for 17-20 minutes, rotating halfway during the baking time.
- When the cake layers are done, cool on a wire rack for 5-10 minutes before removing from the pans on a wire rack to finish cooling completely. Make sure the cake layers are completely cool before frosting.
Buttercream Frosting
- In a stand mixing bowl, add unsalted butter and beat for about 30 seconds.
- Add vanilla and milk, and mix until combined.
- Gradually add the confectioner's sugar, 1/2 cup at a time. Combine completely before each addition. Make sure the frosting is completely smooth before mixing gel food coloring in.
- Divide the frosting in half. Half will be used for frosting the cake base and half will be further divided into colors for decorating the unicorn mane.
- Divide the buttercream frosting into 3 equal bowls (or however many colors you wish to do). Add gel food coloring, and mix until the color is even. Add each bowl of frosting into piping bags with desired frosting tips. Set aside until ready to decorate.
Assembling the Unicorn Rainbow Cake
- On a rotating cake stand, add a cardboard cake circle, add the first layer (red), add a little frosting to make a thin layer between the cake layers, add the 2nd layer (orange), and repeat with yellow, green, and purple cake layers. Use the remaining white frosting to frost the outside of the cake using an offset spatula and cake smoothing comb or bench/dough scraper. To get a smooth surface, you may need to refrigerate the cake before putting the final white layer on, depending on the temperature of the room you are working in.
- Add the unicorn horn cake topper, the eyes, and the ears. (the unicorn cake topper that I use is linked in the recipe card below).
- Now the fun part! Pipe the 3 frosting colors with tips to make the mane and forelock of the unicorn.
- Add sprinkles to the piped flowers on the mane and forelock of the unicorn cake.
- When the decoration is done, allow the cake to firm up in the refrigerator before serving.
Notes
- Storage: Store in the refrigerator in an airtight container (I used the cake carrier linked below), and consume within 3 days.
Recommended Products
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Pyrex Prepware 2-Cup Glass Measuring Cup
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Sweetworks Celebrations Candy Pearls Shaker Jar, 5 oz, Shimmer Bright Pink
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5pc Cooking Tweezers Precision Kitchen Plating Tweezer Stainless Steel Curved Tongs for Baking Decorating Beauty
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Ultra Cuisine 100% Stainless Steel Wire Cooling Rack for Baking fits Half Sheet Pans Cool Cookies, Cakes, Breads - Oven Safe for Cooking, Roasting, Grilling - Heavy Duty Commercial Quality
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AmazonBasics Stainless Steel Wire Whisk Set - 3-Piece
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WIlton Cake Carrier and Server with Locking Lid
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Ateco 612 Revolving Cake Decorating Stand, 12" Round, Cast Iron Base with 1/8" Aluminum Top
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Ateco Professional Cake Smoothing Comb
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Yashell 9625321410 Topper, Reusable Gold Horn,Ears and Eyelashes Cake Value Set for Unicorn Party Decoration for Baby Shower,Weddin
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RFAQK- 90 Pcs Russian piping tips set with storage case - Cake decorating supplies kit - 54 Numbered easy to use icing nozzles (28 Russian + 25 Icing + 1 Ball tip) - Pattern chart, Ebook User Guide
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Sweetworks White Pearl Sixlets 1 lb Bag
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Wilton 710-1174 Sugar Pearls, Silver, 4.8 Ounce
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Food Coloring AmeriColor Student Kit, 12 .75 Ounce Bottles Soft Gel Paste Colors
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Stainless Steel Mixing Bowls by Finedine (Set of 6) Polished Mirror Finish Nesting Bowl, ¾ - 1.5-3 - 4-5 - 8 Quart - Cooking Supplies
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Pyrex Smart Essentials 8-Piece Mixing Bowl Set
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Homestia Gold Measuring Cups and Spoons Set Stainless Steel 8 PIECE for Dry and Liquid Ingredients Engraved Measurement Heavy Duty Baking & Cooking Utensils
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Wilton Easy Flex Silicone Spatula Set, Your Go-To Tools for Mixing, Folding, Scraping, Cooking and Serving., Blue, 3-Piece
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Icing Spatula, 7.5" - 10.8" - 12.8" Offset Cake Spatula Set with Wooden Handle by 1Easylife, Professional Stainless Steel Cake Decorating Spatulas (4"-6"-8" Blade)
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5x Pizza Pie Server Cake Holder Transfer Triangular Spade Spatula for Cake Baking Wood Wooden Handle Shovel Stainless Steel
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KitchenAid KSM150PSER Artisan Tilt-Head Stand Mixer with Pouring Shield, 5-Quart, Empire Red
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Cuisinart HM-90S Power Advantage Plus 9-Speed Handheld Mixer with Storage Case, White
Nutrition Information:
Yield: 12 Serving Size: 1 sliceAmount Per Serving: Calories: 126Total Fat: 12gSaturated Fat: 8gTrans Fat: 0gUnsaturated Fat: 4gCholesterol: 33mgSodium: 76mgCarbohydrates: 2gFiber: 0gSugar: 2gProtein: 3g
Please note that the Calculated Nutrition is an estimate at best.
- This post was originally published on 7/28/2019 and updated and republished on 5/2/2021, 12/7/2021, 11/30/2022
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This is not enough batter for the cake. The layers came out more like crepes. I would suggest you triple the recipe.
Thanks for letting us know. It came out perfect for us using the exact cake layer set that I mentioned. Did you use the same one or a different one?
No I didn’t. I didn’t read all the blabber I just went to the recipe which maybe many people do. Maybe you could put in the recipe to put “pour the batter into 6 inch cake pans” or put that you are using 6 inch cake pans somewhere in the recipe itself as they are not a popular size to use. I used 9 inch pans. It still came out good enough.
I’m sorry you didn’t like the post/recipe, I was just sharing this family recipe and what we did and used to make it. Have a wonderful rest of the week!
I loved how the cake looked, I followed the instructions and unfortunately I did not like it at all. This is pure sugar, almost zero flavor. 🙁 good for kids tho. Thank you for sharing
Help! The icing is literally sliding off. The cakes been cooling for hours, so it’s not that. It’s seems a little thin?
Can I add more powder sugar to thicken it? Or do you have another suggestions?!
Thank you! I’m looking forward to the final product!
Kara
Boerne, Texas
I just saw this. Yes, add more powdered sugar to the frosting to thicken it. It depends also on the temperature of the room, that could be a factor. I hope it was able to work out! Best of luck!