I think you all know what this time of year is. Yes, I know it’s Thanksgiving, but more importantly, it’s also Robin’s birthday. My little sister. Who loves cake. And every year she chooses to visit us for her birthday. She could spend her precious Thanksgiving break anywhere, and yet for the past 3 years, without hesitation, she’s come to Nashville. Honestly, I think it’s because of the cake.

Last year’s cake was pretty darn delicious (and pretty tall too) in all its chocolatey goodness. But I really think I’ve outdone myself this year.

What, you say? That cake doesn’t look like anything special… it looks like just a plain old white cake with a shaky piped greeting…

Well, I say to you, let me cut you a piece…

Bam! Didn’t see that one coming, did you?

Indeed, I tackled in the infamous Rainbow Cake, as seen on Martha Stewart and I’m sure countless other blogs. So no, it’s not original. But that doesn’t make it any less fabulous.

I’ll admit, it wasn’t easy, and I joked that this cake was doomed from the start. From an overly-bubbly and oddly textured cake, to cake layers flying through the air and landing on the floor (thanks, cats!), which lead to a necessary rebaking of the green and yellow, to fingertips meeting with sharp knives, to an entirely too-large batch of buttercream that kept my mixer huffing and puffing for nearly 75 minutes… no, it wasn’t easy at all. But the reaction, the surprise when you make that first cut, that alone made it entirely worthwhile. Robin has officially declared this her Favorite. Birthday. Cake. Ever. Success!

I better start planning now, because I really have no idea how I’m going to top this one next year…

Rainbow Cake with White Chocolate Buttercream

This recipe is a bit uneven. I used 6" pans, and the layers were too thick and and I had way too much frosting. I think it'd be better suited to a 7" or even 8" cake, so adjust as necessary depending on the size of your cake pans.


Cake recipe from Cooks Illustrated. Frosting recipe from Martha Stewart.


Ingredients:

For Cake:

2 1/4 cups cake flour (9 ounces)

1 cup whole milk, at room temperature

6 large egg whites (3/4 cup), at room temperature

2 teaspoons almond extract

1 teaspoon vanilla extract

1 3/4 cups granulated sugar (12 1/4 ounces)

4 teaspoons baking powder

1 teaspoon table salt

12 tablespoons unsalted butter (1 1/2 sticks), softened but still cool

Red, orange, yellow, green, blue, and purple gel food coloring


For Frosting/Filling:

2 1/2 cups granulated sugar

10 large egg whites

2 pounds (8 sticks) unsalted butter, cut into tablespoons, softened

2 teaspoons pure vanilla extract

1 pound best-quality white chocolate, melted and cooled


Directions:

Preheat oven to 350 degrees. Prepare your cake pans by first liberally buttering the pans, then line the bottoms with parchment paper rounds. Butter the rounds and set aside.


Pour milk, egg whites, and extracts into 2-cup glass measure, and mix with fork until blended. Mix cake flour, sugar, baking powder, and salt in bowl of electric mixer at slow speed. Add butter; continue beating at slow speed until mixture resembles moist crumbs, with no powdery streaks remaining. Add all but 1/2 cup of milk mixture to crumbs and beat at medium speed (or high speed if using handheld mixer) for 1 1/2 minutes. Add remaining 1/2 cup of milk mixture and beat 30 seconds more. Stop mixer and scrape sides of bowl. Return mixer to medium (or high) speed and beat 20 seconds longer.


Divide batter evenly between six medium bowls. Add enough of each color of food coloring to each bowl, whisking, until desired shade is reached. Transfer each color to an individual cake pan. Transfer to oven and bake until a cake tester inserted into the center of each cake comes out clean, about 15-25 minutes (working in batches if necessary).


Let cakes rest in pans for 3 minutes. Loosen from sides of pans with a knife, if necessary, and invert onto wire rack. Allow to cool completely. At this point, the layers can also be wrapped in plastic wrap and frozen.


To make frosting, put sugar and egg whites in the heatproof bowl of an electric mixer, and set over a pan of simmering water. Whisk constantly until sugar is dissolved and mixture registers 140 degrees on an instant-read thermometer.


Transfer bowl to an electric mixer fitted with the whisk attachment; beat on medium-high speed until fluffy and cooled, about 10 minutes. Continue beating until stiff peaks form.


Reduce speed to medium-low; add butter by the tablespoon, beating well after each addition. Beat in vanilla and white chocolate. (Any leftover frosting can be refrigerated in an airtight container up to 3 days or frozen up to 1 month.)


To assemble, using a serrated knife, trim tops of cakes to make level. Place four strips of parchment or waxed paper around perimeter of a cake stand or lazy Susan. Place the purple layer on the cake plate. Scoop a 1/2 cup (or more for a larger cake) buttercream filling over the first layer and spread with a small offset spatula so it extends just beyond edges. Repeat process with blue, green, yellow, and orange layers.


Place the remaining red layer on top, bottom-side up. Gently sweep away any loose crumbs with a pastry brush. Using an offset spatula, cover the top and sides with a thin layer of frosting (also use any of the excess frosting visible between the layers). Refrigerate until set, about 30 minutes.


Using a large offset spatula, cover cake again with remaining frosting.


Did you make this recipe?

Let us know what you think!
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117 Comments Leave a Comment »

  1. is there anyway to make this using less layers? I would like to make this using christmas colors and only maybe 3 or four layers.

  2. That is BEAUTIFUL! Your sister is so lucky!

  3. Stunning vivid colors in your cake! What a nice sister you are!!! Beautiful cake – love the decorating you did.

  4. Happy Birthday to your Sister! I know she loved her cake- so beautiful and very impressive!

  5. It may have been a pain to make, but WOW. The cake is gorgeous! You did a fantastic job. I don’t envy you having to top that next year!

  6. what a fun cake! i love the vibrant colors!:)

  7. Beautiful job!! I’ve been wanting to make it since seeing it done on the Martha Stewart show.

  8. You get my vote, not just because I feel sorry for you with all the disasters and the 75 minutes you had to listen to your stand mixer run! :)

    It’s gorgeous! What kid wouldn’t love this?

  9. You say there was way too much frosting…

    Was there too much frosting for the cake? Or was it just too much volume for your mixer to handle? If it was more than needed for the cake, then how much would you cut the frosting recipe?

    Thanks!

    • Both. The meringue took 30-40 minutes to cool to room temperature, vs. like 10 minutes with smaller, cupcake-size batches. But it ended up being way too much frosting for the cake anyway, I’ve got about 4 cups left that I froze. Maybe more appropriate for an 8 inch cake, not 6?

  10. Gorgeous!

    I voted for you too! Good luck!

  11. This is a truly awesome cake! I need to get better at frosting…

  12. Wow, what a colourful cake!
    :-) Mandy

  13. Wow you totally rocked the rainbow cake. Just gorgeous!

  14. GORGEOUS!!!!!! (And I love the photography too!)

    I’ve wanted to try one of those for awhile. Bravo for making it happen — it looks absolutely perfect! And completely delicious. :-) Hope you enjoyed it!

  15. wow that turned out beautifully!

    I’m going to go vote for you right meow!

  16. Oh my gosh! This is amazing! I’ve never seen it before, so I wasn’t expecting all that colour. What a lucky sister you have! x

  17. This looks so yummy!!!!!!!!!!!!

  18. That is so beautiful Lindsay. I really love the second picture- all the lovely bright colors against the black backdrop…my daughter would absolutely love this for her birthday next month!

  19. I think baker’s are artists. I love beautiful photos of cakes and your’s is absolutely splendid. Happy Birthday to your sister. Yummy & Beautiful.
    xx’s

  20. So pretty! You’re right though – the green and yellow layers do look a little more evenly textured than the others. How weird! I’m glad it was still a hit though!

  21. This is SO pretty! I love that it looks like a simple white cake… And it’s not at all! :)

  22. Your Sis is awful lucky! Pretty cake.

  23. As a mom with TWO December birthdays to plan, I luv this cake! It is such a challenge to make the day special in the midst of all the holiday goodies! This cake is a winner! I know my family would love it!

  24. how amazing is this cake?! LOVE it!

    http://www.ThePantryDrawer.com

  25. AAAAA-mazing! This cake is so beautiful and you did such a great job with it! I just love it!

  26. This is beautiful! I can only imagine how much patience was required. I don’t have the patience to make a regular, normal, one-layered cake without frosting – so I am very impressed. And it looks like it produces monster slices.

  27. consider me impressed :)

  28. Wow that is one epic cake! It’s just magnificent :)

  29. My gosh that is too good to be true. I’d love that for my birthday. Looks delicious too!

  30. Gorgeous! Great job! Gonna have to give this one a whirl some time. I’ve done rainbow cupcakes but this beats those hands down!

  31. Alright, the rainbow is beautiful, but the fact that it uses ALMOST TWO AND A HALF POUNDS OF BUTTER is even more beautiful.

  32. This is one of the best looking cakes I’ve ever seen! Beautiful job, especially after all that you endured!

  33. Wow! Just stumbled upon your blog, and what an incredible, technicolour introduction. Not only do I Want. That. Cake. Now. I also want to read more of your recipes. Hurrah!

  34. what a gorgeous cake! and yes it is hard work isnt it but SO SO worth cutting into it and seeing all the bright colours shining out :D

  35. Wow! That is one impressive cake. And you have much more patience than I do. :)

  36. Wonderfull, colourful cake! Thank you :)

    yemek tarifleri
    Aktifmutfak.com

  37. WOW, that is a cake that would make Bettie Landis proud!!! Great job Lindsay.

  38. absolutely breathtaking!!!!! first time i dropped by your site and this is what i’m greeted with. i’ll be hungry for more!!!! such inspiration! cheers!

  39. I love how your cake came out, I will definitely give it a try. Maybe red and green for xmas? Either way itll be delish!

    http://decupcakecriminal.blogspot.com/2010/08/homemade-green-seasoning.html

  40. It’s fabulous indeed! I still haven’t found the courage to attempt it myself so great job!

  41. The cake is very amazing! Just like the dream come to reality.

    A great job!

  42. i love, love, love this cake! it’s almost too much fun. i’ve made a variation on the rainbow cake, and i did all my layers in very light pastel colors. it was gorgeous, but indeed this cake is a labor of love!

  43. It is beautiful! I hope you win! Good luck! :) #butterlove

  44. I discovered this cake on whisk-kid’s blog. She was the one on Martha Stewart baking this cake. She always has wonderful recipes (: You do too, I think you did a beautiful job with this cake!

  45. Love it and you got my vote!

  46. It may not be original, but it’s the first time I’VE seen it! And it’s breathtaking. Happy Birthday to Robin, and so happy she enjoyed the cake!!!! And cheers to the big sister, too, for making it so special.

    [K]

  47. There is some major good awesomesauce in here! Kudos on the fine work :) Nomnomnomnomnom…

  48. that cake looks awesome! may i ask what gel food coloring you used? i am from germany and we don’t have those really vivid food coloring here but a friend of mine is in the usa right now and she would bring me some when i tell her which ones. ^^

  49. Totally amazing! I just showed this beautiful cake to my husband, my birthday’s coming up ya know! I’d better get the ingredients together, (and make it myself) ;)!
    voted by the way, hope you win!

  50. As a Color Specialist, I’m impressed too! I’ll have to write about this beauty

  51. This is a link to the post on Whisk-Kid’s blog, as Serena mentioned, she was the one who made the cake on Martha Stuart: http://whisk-kid.blogspot.com/2009/08/say-it-with-cake.html
    Your cake is aboslutely gorgeous, I just wanted to give Whisk-Kid a nod!

  52. I’ve seen several of these, but yours is by far the most beautiful. I like the thicker cake layers. Sent this link to my granddaughter, who made the cake for a New Year’s sleep-over, and she is just 12! Thanks for the recipe.

  53. F-A-B-U-L-O-U-S!!!!!!!!!!!!!

  54. LOVE love love this.

    sara

  55. So i attempted this recipe a couple months ago pretty much an epic fail. What did you do for the layers of cake be even? Also did you modify the frosting recipe for it to be as much as it should be?

    • Sorry to hear! I divided the batter using a kitchen scale so each layer had exactly the same amount. And then when the layers had baked and cooled I leveled them, making sure each layer was the same height. The cakes rarely come out of the oven perfectly level so this step is typically necessary. The frosting recipe posted is exactly what I made. My cakes were 6″ and I had about twice as much frosting as needed. Probably even too much for 7 or 8″ cakes, but frosting can always be frozen and used for another purpose.

  56. ok so i am going to try this! so excited. I just wanted to know, I want to make sure the colors are as bright and vivid as you have here. I’ve never used gel coloring before (or any coloring really) and I have no idea how much to add into the batter. Do the cakes come out of the oven looking as bright as the batter with the coloring in it looks? Or does it get duller in the oven so then I would need to make it extra dark in the batter?
    it’s gorgeous!

  57. This is so cool! A friend of mine made a similarly colored cake that was swirled, but yours is much more elegant. So playful!

  58. That is a beautiful cake! I love rainbows and this makes one believe they can now be eaten :)

  59. Wondering if it would work with a white chocolate ganache instead of the buttercream?

  60. i love this cake it really very nice sososososos lovely . incredible thinking . WOW

  61. I LOVE THIS CAKE! I am currently wracking my brain for occasions where I might be able to make it for a crowd… I love it that much! I will make up some kind of special occasion if one doesn’t present itself soon… gay pride, maybe??

  62. Now this I didn’t expect. So much yummyness in the first slice. And im sure it tastes as great as it looks.

  63. This is AMAZING!!! Must be so yummy!

  64. What a vibrant investment of time! I may not be up to the challenge of all those layers, but I love the idea that I now can color-coordinate the inside of a cake and surprise everyone. Thanks!

  65. I was just wondering – did you use confectioner’s sugar in the frosting? Or granulated? I assumed it was confectioner’s… but mine seemed… off. Perhaps I did something else wrong.

    • This particular frosting is a swiss meringue, which calls for granulated sugar. Sorry for the ambiguity, I’ve updated the recipe to be more specific. :)

  66. This cake is beautiful. The colors are so vivid.

  67. Wow that cake captured my attention on the front page, no wonder this is the most popular post. This looks like it will be the perfect cake for my nieces birthday that is coming up, so i’ll test it out and see if it turns out as nice as yours :)

  68. This is truely awesome! Do you think the same effect could be obtained by just using a betty crocker white cake mix (where you only add eggs,water, and oil) and just adding the food coloring?

  69. This is even prettier than Martha’s. Now that is a difficult feat!

  70. So much frosting! So little cake lol

  71. WOW! This cake looks amazing! I just got done making this cake. I used 8″ round cake pans and doubled the recipe. That cake tastes AMAZING! and looks great too! You did a fantastic job, I can’t wait to see what mine turns out to look like. I made it for my own birthday! (:

  72. hahaha, nice surprise, I love it!

    @BMBills6

  73. HI,

    I used your recipe to make this cake and its the best cake I have ever made. Thank you. I will be making one for my brothers wedding next month and I am looking forward to their faces when they cut it!

  74. I meant to mention this when I saw you last night at Porta Via but I saw some baking-fanatic cousins of mine in Ohio this weekend and happened to mention your blog. They both are avid readers and mentioned the rainbow cake! I wanted to pass their kind words along. They couldn’t get over how amazing it was. And I totally agree — this is SOME CAKE!

  75. This rainbow cake is so coool. I want to make this!

  76. That is AMAZING! I can only imagine how much time that took! Seriously…jaw on the floor amazing!

  77. This cake is so cute and so nicely made! Is it possible to make a rainbow cake without baking each color separately?

  78. I love these rainbow cakes, and even if it isn’t the “original” I think it is still amazing!

  79. This cake is jaw dropping. I have never seen a rainbow cake as perfect and colorful. I MUST attempt it. I think I will try doing it gluten free as my fiance is celiac, but since GF cake doesn’t rise as much, it woudl be suitable for the number of layers required. Anyway – AMAZING job. I HAD to comment.

  80. AWESOME! I have never seen anything like this!

  81. i know this is late for a comment, but i thought i would add, i am baker did a version of a rainbow cake, using only fruit juices to attain the colors. seemed like an interesting idea, and it would add more flavors to the layers, i think it might be fun to try.

  82. It’s amazing!!! Congrats!

  83. I feel inspired! It’s been a while since I had time to make a cake, but that used to be one of my main hobbies. Thank you for inspiring me and I WILL make time to make this cake :)

  84. This is a wonderful recipe, thanks so much for sharing. You did a great job with the images too; I will definitely try this recipe this weekend.

  85. Oh my god! -that is one of the most beautiful cakes I’ve ever seen. Was it hard to make? I think I’ve found my dream cake for my birthday :)
    And where did you find the recipe?

    //Maja

  86. This is such a beautiful cake!How far ahead to you make this in advance? How do you serve it? I will need to serve 10-15 people.
    Thanks in advance for any advice!

  87. Totally Amazing. – How long did it take from start to finish?

    http://www.caramelandcocoa.blogspot.com/

  88. WOW this is pretty special, I think I’ll give it a go when I’m feeling up to it, for now I’ll just stare at yours and be jealous!

  89. I can’t believe you made this! amazing!

  90. Amazing :D I’ll sure try it.

  91. One word- WOW. I really want to make this, but am afraid to! I would be in the kitchen ALL day.

  92. That is absolutely and utterly beyond stunning. Wow. There are no words.

  93. Is this vanilla-flavored? And you said there’d be too much icing, so should I divid the icing recipie in half?

  94. OMG……The second i saw this cake i was blown away….I haven’t seen this cake before so its no surprise that i was shocked…..but you have done such a great job on it…..ill defiantly try to make this sometime. The pictures are defiantly impressive.

  95. I’m gonna make this cake someday.
    [adding to bucket list]

  96. wow, this is amazing. i’m attempting this cake right now, as we speak. but i dont think mine is going to be nearly this gorgeous!

  97. I tried it with 8″ pans today and the layers were too thin. I know you said the 6′ was too small, but I’d rather a fluffy cake than flat so I will try again!! Its for my daughter’s birthday! Luckily I attempted it a few days early just in case I messed up. :)

  98. it’s amazing! thanks for share

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