I almost gave up on this rainbow cake when the “sails” started giving me all sorts of trouble but I persisted! What do you think?? You know I’m not usually so bright with my colors but I had a special request from a friend for a cheerful colorful cake.
The cake is vanilla but the buttercreams are flavored with a hint of orange blossom water! I LOVE it, so aromatic and unexpected.
If you find cake decorating to be a bit intimidating then check out my How to Decorate a Cake post, it has lots of helpful tips and a full how to video.
A Few Tips and Pointers
- If you’re not using 6-inch pans, double the recipe for 8-inch pans or triple the recipe for 9-inch pans.
- If you see little clumps of butter after you mix the wet ingredients don’t panic, it all works out by the time you mix in the dry ingredients. You can even use melted butter and warm the milk and sour cream up a bit if you like.
- You can substitute whole milk yogurt for the sour cream if desired, I do it all the time and can’t really tell the difference.
- To get FLAT layers that are moist inside and out try using cake strips! You can buy a set on the shop page or make your own from foil and paper towels at home. I made a whole blog post on it so check it out if you’re interested!
- If you don’t want to make Italian buttercream you can use the American variety. I just prefer the smoothness and taste of the Italian variety. I know it’s a pain to make two different types of frosting though!
- This cake uses two batches of buttercream by the way an American variety for the filling and crumb-coat and Italian for the exterior. You don’t have to follow my lead on that as it is a bit of extra work, regular buttercream will work just fine for the whole cake.
If you’ve tried this cake then don’t forget to rate the recipe and let me know how you got on in the comments below, I love hearing from you!
Rainbow Swirl Cake
A vibrant show-stopping cake that's delicious and surprisingly easy to make! Moist vanilla cake layers covered in creamy Italian meringue buttercream and crowned with white chocolate sails!
Ingredients
INGREDIENTS
For the Cake:
- 1 2/3 cup all-purpose flour
- 1 cup sugar
- 1/4 tsp baking soda
- 1 tsp baking powder
- 3/4 cup unsalted butter room temperature
- 3 egg whites
- 3 tsp vanilla extract
- 1/2 cup sour cream
- 1/2 cup whole milk
- food coloring
For the Vanilla Buttercream:
- 1 cup butter
- 5 cup confectioners' sugar
- 1/4 cup heavy whipping cream
- 2 tsp orange blossom water
- food coloring
For the Italian Buttercream:
- 4 egg whites
- 1 1/3 cups sugar
- pinch kosher salt
- 16 ounces unsalted butter room temperature
- 1 tsp vanilla extract
- 1/4 tsp cream tartar
For the Feathers:
- 1/2 cup candy melt white, melted
Instructions
INSTRUCTIONS
For the Cake:
- Preheat oven to 350 degrees.
Sift the dry ingredients together in a large bowl. Beat the wet ingredients together in a medium bowl. Add the wet to the dry and mix until just combined.
Evenly divide batter into 6 different batches. Color each with drops of food coloring until desired color is reached.
Transfer batter to piping bags. Use 3 buttered and flowered 6-inch cake pans.
Pipe in dollops of the batter, alternating the colors. You can swirl with a skewer around batter as desired.
Bake for 30 minutes. Let cool for 5 minutes.
For the Vanilla Buttercream:
- Beat the butter until light and fluffy. Add the confectioners' sugar and cream and mix.
- Divide evenly into batches and dye with food coloring.
For the Italian Buttercream:
Beat the egg whites, salt and cream of tartar, slowly add in 1/3 cup of sugar and continue beating until soft peaks form. In a medium saucepan add the remaining sugar and 1/3 cup water then place on medium-low heat.
Stir until sugar melts and becomes clear. Maintain at medium-high heat until temperature reads 235-240F.
Run mixer until meringue is cool/tepid. Add room temperature butter into running mixer one tablespoon piece at a time. Add the salt and vanilla.
Beat until butter is combined and mixture has reached a silky consistency.
Reserve about 1/3 cup. Add food coloring for watercolor piping step later.
For the Feathers:
Add dollops of candy melt to parchment paper. Color with a few drops of food coloring. Using a spoon, spread to achieve a feather like shape.
For the Assembly:
Pipe vanilla buttercream between the cake layers, alternating colors.
Once the cake has chilled, pipe Italian buttercream on the outside of the cake. With a steady hand, work your way around the cake until it is completely covered.
Tint with 5 different colors. Dollop on colors with a spoon. Smooth out for a watercolor effect.
Add feathers to the cake.
Recipe Video
Recipe Notes
- If you’re not using 6-inch pans, double the recipe for 8-inch pans or triple the recipe for 9-inch pans.
- If you see little clumps of butter after you mix the wet ingredients don’t panic, it all works out by the time you mix in the dry ingredients. You can even use melted butter and warm the milk and sour cream up a bit if you like.
- You can substitute whole milk yogurt for the sour cream if desired, I do it all the time and can’t really tell the difference.
- To get FLAT layers that are moist inside and out try using cake strips! You can buy a set online or make your own from foil and paper towels at home. I made a whole blog post on it so check it out if you’re interested!
- If you don't want to make Italian buttercream you can use the American variety. I just prefer the smoothness and taste of the Italian variety. I know it's a pain to make two different types of frosting though!
Hi.
This looks great but can you share the instructions for the cake batter as well.
Thank you
Nitya,
Yes!
John
SOOO colorful!!
Looks great! Can’t wait to make this for a birthday cake!
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I loved this cake the colors were perfect for a party I had.
Hi Avery,
Awesome, i’m so glad! I love this cake too, the colors are just as sweet as it tastes!
Best,
John