Rainbow Petal Cake for Beginning Decorators

Calling all the rainbow lovers! Learn how to make this adorable rainbow petal cake. 

Rainbows are happy and perfect for any occasion. Today you’ll learn how to take something everyone loves, Rainbows into a beautiful cake design.  

This rainbow petal cake is made with fluffy vanilla cake layers and rainbow vanilla buttercream. The vanilla cake is a simple recipe to follow and perfect for beginners. 

The bright and bold vanilla buttercream is made with all the colors of the rainbow. One big tip before staring is to use gel food coloring since its concentrated color it won’t loosen the buttercream. 

Here you’ll learn how to achieve this simple yet impressive technique called petals (or pulled dots) effect. This technique can be done on any cake, but what makes this cake so unique is how to alternate the colors to create a spiral effect. 

I can’t wait to see your rainbow petal cake creations! 

Tips for Success: 

• Read through all the ingredients and instructions so you can get a better idea of how much time and what you need to make this cake.
• A single batch of this cake recipe makes three, 6-inch round cake layers or two 8-inch round cake layers. Double the cake recipe to make enough cake batter for three, 8-inch cake layers.
• In this cake recipe, you need 1 cup buttermilk; if you don’t have any buttermilk on hand, you can easily use 1 cup whole milk mixed with 1 Tablespoon lemon juice or white vinegar to make your own. 
• To make cake flour at home, mix 2 ¾ cups all-purpose flour and ¼ cup cornstarch. Sift or whisk together to get rid of any lumps. 
• Be careful not to overmix this cake batter, or else the cake will come out dense. Mix until all ingredients are well incorporated.
• You can bake the cake layers ahead of time. Wrap the cake layers in plastic wrap and freeze up to one month. 
• Food coloring gets darker over time, so it’s best to add the food coloring gradually. 
• You can make the vanilla buttercream a day or two ahead and refrigerate them overnight. Then take them out to come back to room temperature. Make sure the buttercream is at room temperature before re-whipping. 
• For making the petal or pulled dot effect on the buttercream, you’ll need a piping bag for each color, but you’ll also need an offset spatula. You also use a spoon to achieve the petal effect. 
• Serve at room temperature and enjoy! 

What Tools You’ll Need to Make This Cake: 

• 5-quart, Stand Mixer with mixing bowl & paddle attachment
• 3, 6-inch cake pans or 2, 8-inch cake pans
• Offset spatula 
• 8-inch or 10-inch white cake board 
• Serrated knife or cake leveler 
• Turntable 
• Cake scraper or bench scraper
• Whisk or sifter
• Rubber Spatula
• 6, Small mixing bowls
• Non-Stick Cooking Spray and Parchment Paper
• Ice Cream Scooper with Trigger Release (for dividing cake batter evenly)
• 6, Piping Bags (I use reusable silicone bags)
• Cake Stand, optional

Here’s how to make this Rainbow Petal Cake that’s bright and bold! 

Let’s Get Baking! 

How to Make Light & Fluffy Vanilla Cake 

1. Preheat the oven to 350 °F. Spray three 6-inch round cake pans with non-stick spray, line the bottom of each pan with parchment paper and spray again. Set aside.
2. In a medium-size bowl, whisk and stir together the flour, baking powder, and salt. Set aside. 
3. In the stand mixer bowl fitted with a paddle attachment, beat the butter, oil, and sugar on medium-high for 5 minutes.
4. Add the eggs, one at a time to the stand mixer bowl and beat on medium until well incorporated.
5. Turn the mixer on low and add the flour mixture to the butter mixture until fully incorporated. 
6. Pour in the buttermilk and vanilla extract. Mix on medium for another 30 seconds and scrape down the sides of the bowl. 
7. Evenly distribute the cake batter among the three cake pans and bake for about 30-35 minutes or until a toothpick inserted into the center of each cake comes out clean or with just a few moist crumbs.
8. Remove cakes from the oven and let cool in pans for 10 minutes before inverting onto cooling racks to cool completely. Wrap cakes in plastic wrap and place them into the freezer to chill for 30 minutes to 1 hour. 

How to Make Creamy Vanilla Buttercream 

1. In the stand mixer bowl fitted with the paddle attachment, beat the butter until light and fluffy, about 2 minutes.
2. Turn the mixer to low and add the salt and vanilla. 
3. Next, gradually add powdered sugar, followed by the cream. Mix on medium-high speed for about 5 minutes, until light and fluffy. Scrape down the sides of the bowl. 
4. Before using, turn the mixer on low and mix for 2 minutes to push out any air bubbles or use a rubber spatula to push out the air bubbles. (You may need to repeat this step when frosting the outside of the cake). 
5. Divide buttercream into six bowls (reserve some white buttercream for later, if necessary to refill another color). 
6. Then color with deep pink, Georgia peach, lemon yellow, leaf green, sky blue, and brite purple. Place the colored buttercreams into individual piping bags, set aside. 

Putting It All Together

1. Remove the cake layers from the freezer and unwrap the cake layers. Next, use a serrated knife to cut off the dome of the cakes to make the layers flat and even. 
2. Add a small amount of buttercream onto the center of the cake board. Layer one cake layer, cut side up onto the cake board. Pipe a ring of pink buttercream in the center of the cake, followed by rings of peach, yellow, green, blue, and purple buttercream on the outside. Use an offset spatula to smooth the buttercream layer.  
3. Place another cake layer cut side down over the top. Repeat the process for another layer — Crumb coat with buttercream and freeze for 30 minutes. 
4. Starting from the bottom of the cake, pipe a single dot about 1-inch of one color buttercream. Then pipe another color dot above the previous dot and continue to pipe dots in a straight line up the cake alternating the buttercream colors. 
5. Use an offset spatula to press and pull the dot towards the side of the cake. Repeat the process until you have one column completed. (Scrape off the colored buttercream into a bowl to keep the spatula clean in between each color). 
6. To start a new column, pipe the next dot overlapping the previous pulled dot. Alternate the colors to create a petal effect. Repeat the process all over the whole cake. 
7. Serve at room temperature and enjoy! 

You May Also Enjoy: 

• Rainbow Drip Cake (tutorial)
• 14 Fun & Whimsical Cake Designs for Beginner Bakers (tutorials)
• How to Fill, Stack & Crumb Coat a Layered Cake (tutorial)
• How to Decorate Your First Cake (free course) 
• Cake Decorating Tool Kit (24-piece tool kit with free shipping)
• Cake Decorating Creator Program (ultimate bundle)  

Now that you know how to make this simple yet impressive rainbow petal cake design, I hope you continue to practice and gain confidence in the kitchen to take on any cake challenge. 

Are you struggling with cake decorating and need more one on one help? I’m now offering an online cake course called Cake Decorating for Beginners. This cake course will teach you everything you need to know to make beautiful cakes at home. You’ll get video and written tutorials so you can have the best experience!

It doesn’t matter if you are brand new to baking or have dabbled in decorating cake before; this Cake Decorating for Beginners Course will help you. My promise to you is if I could do this, then you can do this too! CLICK HERE TO ENROLL 

Happy Decorating! 

Watch The How-to Video Below: 

Hey, if you liked this tutorial, you really should check out, Cake Decorating Creator Program, my online cake course. I coach you on everything I teach on these cake tutorials so that you can uplevel your baking and decorating skills. We 10x it so you get the results you want most. Like any new skill, it’s important to learn from the ground up to build a foundation, so take on any cake challenge. It is an investment your future self will thank you for. Check it out at XOKatieRosario.com/online-cake-course. I will see you there.

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