Rainbow Birthday Cake

Rainbow Birthday Cake

As much as I love striped cakes....

I love striped cakes, but to be honest – sometimes getting super clean stripes with a cake comb is frustrating even for experienced cake decorators. So it follows that it would be hecka intimidating for beginners! 

I was working from a picture a client provided that had semi-messy stripes when I made this cake. No one caught me complaining! 😉

Since the cake contains six layers, it's easy to use the cake layers as a guide for how thick to make each stripe. Pipe on each stripe next to its corresponding cake layer, then smooth it all out with a cake scraper!

Pretty sure this was the easiest striped cake I’ve ever made, and I loved the look when I was done!

Recipes, instructions, and links to supplies available online are below!

Feel free to email me with any questions, and enjoy!

(Disclosure: As an Amazon associate I may earn from qualifying purchases, and my posts often contain affiliate links. If you click a link and make a purchase, I may receive a commission at no extra cost to you!) 

Rainbow Birthday Cake

Rainbow Birthday Cake

Rainbow cakes never seem to stop being popular. This Rainbow Birthday Cake recipe contains all my tips for creating a beautiful bright cake!
Prep Time 25 minutes
Cook Time 37 minutes
Decorating time 1 hour
Total Time 2 hours 2 minutes
Course Dessert
Cuisine American
Servings 16 servings
Calories 774 kcal

Ingredients
  

Vanilla Cake Layers

  • 3 ¼ cup all-purpose flour
  • 3 cups granulated sugar
  • 2 ½ teaspoon baking powder
  • 1 teaspoon salt
  • 1 cup unsalted butter (or 2 sticks, room temperature)
  • 1 cup egg whites (about 7 eggs, or use egg whites from a carton to avoid wasting the yolks)
  • 1 ½ cups buttermilk (room temperature)
  • 2 teaspoons clear vanilla extract

Cream Cheese Buttercream Frosting

  • 8 ounces cream cheese (one package; softened)
  • 1 cup butter (two sticks, softened)
  • 6 cups powdered sugar
  • 1-2 Tablespoons milk
  • 1 Tablespoon clear vanilla extract
  • ¼ teaspoon salt (if using unsalted butter)
  • 3-4 large drops Red, orange, yellow, green, blue, and purple gel food coloring (all the colors I used are available in this set)

Instructions
 

Vanilla Cake Layers

  • Preheat oven to 350°F. Prepare three 8 inch round pans with baker's floured spray (or grease and line with parchment rounds).
  • Mix together all dry ingredients (flour, sugar, baking powder, and salt) in a stand mixer with a paddle until fully combined. Mix chunks of room-temperature butter slowly into the dry mix, on a low speed. Continue to mix until no large chunks of butter remain, and the mix becomes crumbly.
  • Pour in egg whites and mix on low until just incorporated. Mix in the buttermilk in two parts, on a low speed. Add in vanilla, and mix at a low speed until fully incorporated. Scrape down the sides of the bowl with a spatula, then beat on medium speed for about 30 seconds.
  • Divide batter evenly between the prepared cake pans (I find a kitchen scale helpful for this part). This guarantees your layers will bake to be the same height.
  • Bake for 34-37 minutes (or until a toothpick comes out clean). Allow cake layers to cool for 10-15 minutes on a wire cooling rack before removing from pans. Cool completely before frosting. Set in the fridge or freezer to accelerate the cooling process if desired. (This is a great time to make your frosting!)
  • Once the layers have fully cooled, they can be leveled and any caramelized bits can be trimmed from the sides / top of the cake using a serrated knife if desired. Cut each layer in half horizontally, making a total of 6 cake layers. (Be sure the layers are completely cooled or chilled before leveling or trimming. If you try while they’re still warm, they will likely crumble or break.)

Cream Cheese Buttercream Frosting

  • Beat together softened cream cheese and butter; slowly add in powdered sugar alternating with milk until frosting reaches desired consistency. Add vanilla and salt if needed and beat until well combined.
  • Divide frosting into 6 parts and color them red, orange, yellow, green, blue, and purple.

Assembly

  • Place a smear of frosting on your cake circle (to keep the cake from sliding while you decorate it) and center your first cake layer in the center of the circle. Spread the layer with red frosting. Center your next cake layer on top.
  • Repeat the process with your remaining cake layers, with orange, yellow, green, blue, then - you guessed it - purple frosting on top.
  • Now you're ready to crumb-coat . If you're unfamiliar with crumb-coating, it's just what it sounds like – spreading a thin layer of frosting over the entire outside of the cake to keep crumbs out of your final layer. I usually do this with my large offset spatula. (Don't sweat it if the colors get a little muddled; you'll add another layer of frosting in the next step!)

Decorating

  • Let your crumb coat set in the fridge (about 10 minutes), and transfer the remaining colored frostings to each of 6 piping or zip-lock bags. Use the piping bags to add your final layers of each colored frosting, and smooth in even swipes with your bench scraper. (I don’t recommend starting the smoothing process with an offset spatula at this step; it’ll probably smear the colors too much.) As you smooth, you may need to fill some holes with more frosting from your piping bags or with a small offset spatula – continue filling and smoothing until you’re happy with the frosting!
  • Use the bench scraper to pull in the edges and smooth the top of the cake – add the cake topper and you’re done! Congratulations!

Video

Notes

(Please note nutrition information is an estimate and may not be exactly accurate.) 

Nutrition

Serving: 1sliceCalories: 774kcalCarbohydrates: 99gProtein: 9gFat: 38g
Keyword Rainbow Birthday Cake
Tried this recipe?Let us know how it was!

Mentioned in post: Vanilla Cake Recipe, Cream Cheese Buttercream Frosting

Did you make this Rainbow Birthday Cake? 

Send me an email and let me know how it went – or make my day and find me on Pinterest or on Instagram and tag @IntensiveCakeUnit in your photo!

You can also add a comment or a recipe rating at the bottom of the page! 🙂

Other recipes you may love…

(Click / tap the photos to be taken to the recipe pages!)

Leave a Comment

Your email address will not be published. Required fields are marked *

Recipe Rating