Wednesday, September 23, 2009

Super Epic Rainbow Cake

First spotted this cake on Whisk Kid - of course I bookmarked it and knew that this, this was going to be Bear's birthday cake. How could it not be? It's unbelievable!

Tinting the cake batter was no big thing, once I did a bit of research and decided to shell out $16.00 for a box of fancy Wilton food coloring gel. That stuff is incredible. The colors, as you can see, were intense and true - although the picture makes the red and orange look similar, in reality they were obviously different.

In my opinion, the most difficult and labor intensive part of this whole thing was the buttercream icing. She's a fickle bitch. I went with a recipe I've never tried before - but it's Bon Appétit, it'll work, right? Remind me (again, please) that trying out a new recipe on something that has to be seen by other people is never a good idea.

While I was beating the egg whites and sugar for the second batch (with a hand mixer - I really, really need a stand mixer!!!), my other hand was stirring the sugar syrup on the stove. The thing about sugar is that when it starts to caramelize, it happens fast. I did take the pan off the heat before the browning started - but as I was pouring it (in a slow, steady stream so as not to cook the egg whites), the residual heat from the pan nearly caramelized the sugar! In layman's terms: almost caramelized sugar syrup = golden sugar syrup = pinkish buttercream.


Because I'm frugal cheap, I refused to throw it out. Into the fridge it went. And onto the third batch of buttercream. Please keep in mind that each batch of buttercream calls for 5 egg whites and a cup of butter, plus sugar (negligible - I bake, sugar is always on hand). My patience was running out just as fast as the supplies!

I figured I had this recipe whipped by now, and sure enough, the third batch turned out beautifully - silky smooth, and it melted on the tongue. I'd run out of butter and eggs so I decided I'd layer as much of the cake as I could and finish the rest the next day.

One more batch of buttercream the next morning (yeah, I've got that recipe wrapped around my little finger now), and I came to a brilliant conclusion for the pink buttercream: crumb coat!! It wouldn't be noticeable to anyone but me, and that would leave more of the bright white perfect buttercream to frost the rest of the cake with.

When I forced myself to quit fussing with the icing, laid down my spatula and called it good - I was sort of shocked at the sheer size of the finished cake. Sure, the six cake layers are quite thin - but pile icing in between each one of them, frost the top and sides of the cake and goodness gracious you've got yourself, well, an Epic Rainbow Cake.

It went over well at the party though. I was so nervous cutting into it - my hands were shaking. But when I slid that first slice out and saw that hey! It worked! And everyone gasped and oohed and aahed...I was happy. Bear loved the icing.

My warnings?

Go ahead, make the cake. It's a showstopper, for sure. However - don't make it for a small gathering. Because of all of that gloriously rich icing, even the thinnest of slices may not get finished. It's a terribly filling cake - I have a quarter of it in the freezer yet.

The buttercream recipe I used isn't terribly sweet, which in my opinion is a good thing when you're using this much of it.

Super Epic Rainbow Cake
Whisk Kid
Makes one (gigantic) 9 inch six layered cake

1 cup butter, room temperature
2 1/3 cups sugar
5 egg whites, room temperature
2 teaspoons vanilla
3 cups flour
4 teaspoons baking powder
1/2 teaspoon salt
1 1/2 cups milk, warmed to room temperature
red, orange, yellow, green, blue and purple food coloring

Preheat oven to 350F. Grease your 9 inch cake pans (I have 2 commercial pans, I just kept washing, re greasing and re lining) and line with parchment on the bottoms.

Sift together the flour, baking powder and salt. Set aside.

Cream the butter and sugar, then add the eggs whites a little at a time. Add vanilla and mix till blended. Alternating between wet and dry, add the milk and flour mixture.

Divide the batter amongst 6 bowls - Kaitlin suggested doing this by weight, but I just used a 1 cup measuring cup to start and as the batter decreased, I used a 1/4 cup measure till all the batter was gone. Whisk a fair amount of each food color into each bowl, pour into your prepared pans and bake for approximately 15 minutes each.

Let the baked cakes cool in the pan for a few minutes, then finish cooling on a rack.

Basic Vanilla Buttercream

Bon Appétit

5 large egg whites
1 2/3 cups sugar, divided
1 teaspoon vanilla
1/3 cup water
1 pound unsalted butter, diced, room temperature

Note - it is indescribably important to have each and every one of your ingredients at room temperature or your buttercream will fail. That's pretty much guaranteed. Trust me.

Combine egg whites and 1/3 cup of sugar in a large bowl using a mixer. Add vanilla.

Combine remaining 1 1/3 cups sugar and 1/3 cup water in a medium saucepan; stir over medium heat until sugar dissolves and syrup is bubbling.

Meanwhile, beat egg white mixture on medium speed until very soft peaks form.

Increase mixer speed to high and slowly pour hot syrup down the side of the bowl into egg white mixture in a slow, steady stream. Beat until this meringue forms stiff peaks. Allow meringue to cool in the bowl until lukewarm. Do not beat to cool.

Once lukewarm, start beating meringue on medium speed. Gradually add butter, a few tablespoons at a time, beating constantly till each addition is absorbed before adding next. Continue beating until buttercream is smooth.

If buttercream looks 'broken' or curdled, you can try placing the bowl of buttercream over medium heat on a stove burner and whisk for 5-10 seconds to warm slightly, then remove from heat and whisk vigorously or beat again on medium speed. Repeat this process until buttercream becomes smooth. Keep in mind, this may not work and it might not be salvageable.

You will be able to tell when the buttercream is starting to come together by listening to your mixer - all of a sudden it will start to sound as though it is working harder, and then the buttercream will come together quickly.
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  1. Looks awesome but also the things a weight watchers meeting or diabetics support group may cry about lol.

    Wow, mammoth effort Rina! xx

  2. Beautiful, beautiful, beautiful....

  3. I'm making this next week! I already saw it on the original site! I can't wait!

  4. Woah. THAT is definitely an EPIC cake.

    I love it.

    My question is, does it matter what cake & buttercream recipe you use as long as you divide the batter properly to colour?

    I've got a great white cake recipe from when I was studying with a pastry chef (lol it's true!) and I've got a really delicious buttercream recipe that isn't nearly as much work as yours is!

    I want to know if I could get away with using those? I should also send you the icing recipe... you won't have to work so hard to get it perfect!

  5. Gorgeous! You did a fantastic job and it looks beautiful. And thanks for sharing your tips. Maybe someday I'll be brave enough to attempt something similar. Maybe.

  6. Hi, I made a Rainbow cake for my 6 yr old's Bday also, and it was a huge hit! As well as a huge cake, oh my! Love those food coloring gels, they work so much better! It was great since each layer was a fruity flavor, so yummy! Stop by and check it out!

  7. Wow, loved this cake. So bright and colorful! Must say.. You have got loads of patience!

  8. HOLY MOLEY mama bear!
    you have one lucky baby bear. I seriously am try to think up an excuse to try this one, but with a cake like this its practically a holiday on its own. wow.
    ps I love the refridgerated cookie recipe, turns out great, I did a double batch and keep it in the fridge/freezer so I have fresh cookies anytime!

  9. Wow, $14 of butter! This is a very special and beautiful cake. I love it!!! So pretty.

  10. Your cake turned out fabulously! It looks gorgeous!

    Sorry to hear that you had trouble with the buttercream! I'm glad you were able to get something to work eventually. I definitely know how that can be ;)

  11. One day you have to run out of recipies.

  12. That is a seriously awesome cake! And so much work, but definitely worth it. I'm wondering if I can do this one for my son's birthday party in December. We'll see how ambitious I'm feeling come time. :)

  13. Holy moly! This is the first time I've seen a rainbow cake. It's unbelievable. And my girl's 6th birthday is coming up...
    I'm not sure if I'm as brave as you. What doesn't kill you makes you stronger, eh?

  14. Hi! I've nominated you for a Kreativ Bloggers award:

  15. Amazing looking cake.
    And AMAZINGLY FUNNY story behind it.
    All I can think is that baby is one lucky little bear!

    Next time: COSTCO. $14 worth of butter is ridiculous.

  16. That is an amazing cake!! I want to make this now for my daughter's birthday!! :D The colors are gorgeous!! (I was looking for a rainbow cake recipe and stumbled across you!)

  17. You are hilarious! I love the commentary, and I empathize with you on the wasted ingredients. Sob, sob, butter in the trash. What an endeavor for Baby Bear! :)

    Thanks for joining the Make it from Scratch Carnival!

  18. That's beautiful; love those colors!

    Buttercream frosting should not require eggs and cooking and that sort of fussing, though. Our recipe uses butter, confectioner's sugar, and a little bit of milk. And I think maybe a tad of vanilla and salt? And you just mix it. We've been using it for years, and I don't recall ever having had it break. Just FYI, 'cause I'd hate for you to have to go to all that trouble again the next time you make a cake.

  19. Wow. Dude, that's one insane cake.

  20. I did this last week with a (GASP) box mix and lemon buttercream. It was a hit at the potluck picnic.
    I found that 10 minutes per layer worked great, and only the thinnest layer of icing between the layers kept the cake from sliding around like a stack of wet plates.
    IMHO, lemon cuts some of the cloying sweetness of the icing. Next time I do this I'm subbing lemon curd between the layers.
    It is a fun cake.

    For some reason OpenID isn't working today...

  21. This is utterly AWESOME!! I can't use regular buttercream down here in FL without it completely melting...I have found a perfect buttercream that tastes good but uses Crisco and can stand the heat and humidity. It works every time. I can feeel your buttercream pain though. Been there.


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