Pastel Rainbow Cake

filed under: White Cakes on October 5, 2016

This cake was a horrible, happy accident. I love the final product, but getting there was no easy task!

Sweet & Fun!

To make the above cake you will need:

white cake recipe – I doubled the recipe (3 layers for the bottom of this cake, I saved and froze the 4th layer) with 8-inch round cake pans, then 1 additional white cake recipe in two 6-inch round cake pans.

buttercream recipe tripled (reserve one recipe for the final piping)

chocolate buttercream

red, yellow, green, blue food color (mix color to make orange and purple)

cake stand, see my cake stand collection here

rotating cake stand

straws or wooden dowels

small offset spatula

bench scraper

#362 large open star tip, see how to store tips here

pastry bag

pastel sprinkles

Just a few things needed to make a beautiful 2-tier cake!

Begin by baking the cakes. I baked three TOTAL white cake recipes. First, I doubled the white cake recipe and baked 4 layers of white cake. (I only used 3 for my cake, so the fourth layer was wrapped and frozen for later use.) I then whipped up another white cake recipe and baked it in two 6-inch round cake pans.

When cakes are done baking and cooled, level them.

Prepare chocolate buttercream. (The little girl that I was making this cake for requested chocolate frosting between the layers so that is I what I did. You can certainly use white buttercream if you prefer.)

Begin by placing first 8-inch round layer of cake on cardboard round and place that directly on top of rotating cake stand. Cover with 1/2 cup to 1 cup of chocolate buttercream. Smooth out with a small offset spatula. Place next 8-inch round layer on top and add chocolate buttercream. Finish with final layer of white cake. (Cake should be 3 layers) Cover the sides of the cake with chocolate buttercream. Chill in freezer while assembling the next tier of the cake.

Place 6-inch cardboard round on the rotating cake stand. Set one 6-inch round layer of white cake on the cardboard. Cover with 1/2 cup of chocolate buttercream. Place the final 6-inch layer of cake on top and fill in the sides with chocolate buttercream. Move this 2-layer cake to freezer.

Prepare white buttercream. Separate buttercream into 7 bowls. (You need to save about 2 cups to cover the top and sides of both tiers of cake in a crumb coat.) Divide the remaining frosting between 6 bowls. You should have about 1 1/2 cups per bowl. Tint pink, orange, yellow, green, blue, and purple. Once you have tinted all of the frosting, place each color in a pastry bag and seal with a rubber band.

Tint pink, orange, yellow, green, blue, and purple. Once you have tinted all of the frosting, place each color in a pastry bag and seal with a rubber band.

Rainbow Frosting! <3

Remove your 3-layer cake that is on the cake stand from the freezer. Cover the cake in a thin layer of white buttercream, this is your crumb coat.

Cut off the tip from the purple bag of frosting. With your cake on the rotating cake stand, press bag of purple frosting against the very bottom layer of your cake and apply pressure with one hand while turning the cake round. Do this twice, or make sure you use enough frosting to cover about 2 inches at the bottom of your cake. (The cake should be about 6 inches tall.)

Repeat this process with the blue frosting. Then repeat that with the green frosting. Make sure just a bit of your green frosting overlaps on top of the cake.

Now take the bench scraper and hold it flat against the side of the cake. Holding your hand steady, start to move the cake stand around, trying not to stop. Go around as many times as you need to create a smooth finish on your cake.

Here is a video on how I did that! (There is a BUNCH of extra steps in this video… just ignore that part!! I am so embarrassed.)

Now! Back to this cake.

Take a straw and insert it into cake. Lift it up just a tad and then cut it so that it is level with the top of the cake. (You can use wooden dowels, but they should be measured and cut ahead of time.)

Set the 6-inch cake stack on top. Repeat the method you used above, only this time, start with yellow. Then orange. Then red. Smooth out the top.

Fill pasty bag that has been fitted with a #362 tip with buttercream. (any large open star tip will work) Start piping out a shell pattern around the base of each cake. Then finish with that same shall border pattern around the upper edge.

Cover the piping with pastel sprinkles and chill until ready to serve!

So! If you saw that video you saw how HORRIBLY I messed up this cake. It was UGLY.

Huh!I mean. I don’t even know. Literally, have no excuse.

But I think it was able to come back nicely to a cake that is at the very least #nothideous. 🙂

Easy & Fun!

If you have any questions please let me know. I am writing this post at 2:00am and I am not sure my brain is working right. 😉

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  • Marcia Burns says:

    You recovered nicely! Final cake is beautiful as always Amanda!

  • Stephanie Diehl says:

    Love that you show us how to fix “disasters”
    Thanks, Amanda!

  • Pearl says:

    Wonderful, wonderful recovery!!!

    I would have eaten it before and after anyway!!

    I love the final product and it is way more than “not hideous”.

  • Andrea Lazarus says:

    I love what you have done with this cake…Please advise me on how I can make a frosting less sweeter.

  • Amy Frye says:

    Great cake! Do you use 2″ or 3″ deep cake pans for your cakes?

  • Julie BURCKHARDT says:

    Can i freeze unused buttercream icing to use At a later date?
    If so, for how long?
    And how far in advance can i make cupcakes?

  • Marian burke says:

    You cakes look so delish so simpel to make your vidio is good shoning how to make thei wis i could kep thia vido

  • Tina Pina says:

    I just love your website, I am Baker. I follow you daily and bake something once a day and share your recipes with friends.

  • Yamuna says:

    Super food thank you….

  • Helena says:

    I love your website and posts, you hmare very creative and it is nice to see when you mess up how you can fix it :-). Thank you! I love the outcome, very playful 🙂

  • Jo says:

    can you recommend a chocolate cake recipe I could use instead of white cake?

  • I Am Baker Logo

    Brand new recipes that people find kinda acceptable.