Tuesday, April 5, 2011

Fat Tuesday: Rainbow Layer Cake

Today is my sweet, fun-loving, adorable, stubborn, blue-eyed baby boy's 4th birthday. He has had a rough go of it lately... a broken leg, a never ending battle over potty training and the whole middle child thing rearing its ugly head. Yet, in the past week or so, he has turned a corner. His cast came off, the potty training beast has been tamed and well, we are working on the middle child thing (two out of three isn't bad). 

To celebrate Ben's 'big boy' status, we are having his official pirate birthday party with the family on Sunday (treasure chest cake and all), but it didn't seem right that he didn't have a cake for his actually birthday too. I mean, you can't have a legit birthday without blowing out some candles. I guess I would have to make two cakes. Oh darn, 'cause I really hate to bake :)

When I asked him what kind of cake he wanted on his birthday, he said a rainbow cake, and then proceeded to sing the rainbow song he learned in school for the next two hours...very loudly. How can they be so annoying and utterly adorable at the same time? Anyway, we are celebrating Ben's birthday rainbow style with this vibrant 7-inch tall rainbow layer cake. I had been wanting to make one of these for awhile, so I was pretty excited with his choice. Thanks, Ben :)

I am almost exclusively a 'from scratch' baker; however, I knew that my white cake recipe would not be able to handle the food coloring and mixing that would be required to get the vibrant colors I needed. Instead I opted for Rebecca Sutterby's popular White Almond Sour Cream Cake recipe. I have had good luck with it when I have used it in the past, and it tastes pretty good. I knew it would work well for this type of cake.

You will need four 6-inch pans for this cake, first dividing the batter equally between four bowls to color, and then pouring it into prepared pans. I used Americolor brand Super Red, Egg Yellow, Sky Blue and a mix of Violet and Regal Purple to color the batter. Use as much or as little color as you desire keeping in mind that the color of your batter stays pretty true to the final color of your baked cake.

While the cakes are in the oven, make your buttercream. I recommend using a recipe that holds color well, otherwise you may have a difficult time getting the colors you are looking for. Since this was for my kids, I opted for an American style buttercream instead of my favorite Swiss Meringue variety.

Once the cakes are out of the oven and cooled, level the tops with a cake leveler or bread knife and start to fill. I typically make a dam of vanilla or chocolate buttercream around the edges of each cake layer before I fill. This is to ensure the filling doesn't seep out of the sides of the cake. However, when you cut into a cake that has one of these dams, you can see it in the sliced piece. Normally, it's not a big deal, but I thought it would take away from the rainbow effect. So, I instead opted to push the filling out to the edges of the cake being very careful not to get any overflow onto the sides.

When the layering is all done, do a quick crumb coat to seal in any crumbs, and stick the cake in the refrigerator until the buttercream is firm to the touch. When it reaches this point, pull the cake out and give it its final coat of buttercream. Stick it back in the refrigerator and let the final coat of buttercream cool for a couple hours in preparation for decorating.

At this point, you can decorate the cake as you choose. Our family is a sprinkle loving bunch. We put them on everything...waffles, pancakes, cereal, doughnuts, ice cream.....whatever. So, it wouldn't be a proper rainbow cake in our family without slathering it in rainbow sprinkles :) I think Ben is going to love it. I will try to post a picture of it sliced after we sing our happy birthdays to Ben!

Happy 4th Birthday Ben! 
It's your day to shine :)


  1. this cake is absolutely beautiful! i've seen many rainbow cakes, but this is the first one i see where icing represents a color! brillant! i might just make it for my daughter's forth birthday next week :) and funnily enough, i made a pirate's treasure chest for her a few weeks ago!

  2. This is such an amazing cake, I love that the buttercream is part of the rainbow. Its Beautiful! Just wondering if this cake would be strong enough to stand being covered in fondant?

  3. How incredible! I've never seen a cake like this before - I'll bet it was a huge hit with your son & everyone who celebrated with him!

  4. Butter Hearts Sugar - It is a really sturdy cake. I have covered it in fondant several times without a problem. Thanks for your comment :)

  5. Could you please explain the technique for how you applied all those sprinkles? It looks so lovely. Did you just apply with your hand or do you have a special way of applying? Please share. Thanks!!!

  6. Hi LezHoppy, The sprinkles were a bit of a challenge. I applied them while the buttercream was cold so that it would not squish through the sprinkles. I basically poured a big bowl of sprinkles and then held the cake at a slight angle in one hand and applied then with the other. Make sure to do this over a cookies sheet to catch all the stray sprinkles. I was a bit of an excise in patience and arm strength... I hope this helps :)

  7. Thank you for the sprinkles information. One more question please, did this rainbow cake use up the entire White Almond Sour Cream Recipe? Did it take the full two boxes of cake mix, or did you only use one-half recipe? Seems with 6" pans 1/2 of the recipe would suffice? I would like to make this cake over the week-end. Thanks!!!

  8. Please tell me if your cake used the full WASC recipe (2 boxes of mex, 2 cups of flour, etc.)I see your cake filled 4 6" cake pans but it seems like the full WASC recipe is way too much batter. Can you clarify please? Perhaps you only used 1/2 the recipe? Thanks so much!

  9. LezHappy - Sorry for the delay in getting back to you...this was a half recipe (one box) of the WASC cake. Hope this helps :)

  10. I love it! I saw it on pinterest and was totally inspired so I made my own and linked back to yours on my blog! Thanks for such a great inspiration!


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