Rainbow Cake

I remember, around a year ago, getting a EUREKA moment.. RAINBOW CAKE!! How cool would it be to bite into a cake that was practically the rainbow? And not in a skittles way! The more I thought about it the more I believed I was a genius. How silly of me to not think of it before?

Obviously I was living under a rock.

I made this cake for my little sisters birthday a few weeks ago after she kept requesting 'the cake she once saw on my laptop'. As we've already established, rainbow cake is not really a new concept, no matter how much I thought I came up with it... but after seeing it as a doodle cake, I loved the idea. Instead of everyone signing a happy birthday card, why not sign a cake instead?!

However, as we all know, things don't always go to plan. This was my first experience of using fondant, and I can't say I'll be rushing to use it any time soon. I had a lot difficulty with making just rolling out the fondant without it sticking to anything. And it kept cracking. And falling apart. And it wouldn't stay smooth. But I put all these differences aside, made the cake, covered it in icing and then fondant and kept it in the fridge overnight so it can be used the next day as a card. 14 hours  later, when I tried to write on the cake with edible pens, it wouldn't work.. 2 hours before the birthday party.. 1 hour.. during the party.. It still didn't work, which completely ruined the whole point of a doodle cake! I can't call it a doodle cake if there were no doodles? What a waste of my efforts.. And I don't even like fondant! 

I came to 2 likely reasons why it didn't work:

1. all 8 pens that I bought were crap

2. The fondant wasn't completely dry and still a bit wet.

I'm going to assume conclusion 2 is the more likely reason, but I can't tell you what I did wrong or how I would have fixed it. So it will remain a mystery. Unless anyone is willing to solve this mystery? 

As you can see from the original doodle cake, the colours of the cake layers are noticeably more vibrant than what I produced, and I suspect its because I used liquid food colouring and not gel like it was suggested, which was because I couldn't find it anywhere in the shops in the UK and kinda decided to do this cake last minute so didn't have time to order it online. Also, the original recipe used swiss meringue buttercream, which I didn't use (because it called for 9 egg whites, and I wouldn't have known what to do with 9 egg yolks! Not including the 5 egg yolks I was already receiving courtesy of the cake.. I couldn't just get rid of 14 egg yolks!) and opted for classic buttercream. I kind of wish that I did use the swiss meringue instead as I imagine the texture would have been a lot lighter and fluffier than buttercream frosting that had been chilled in the fridge for more than 14 hours. Saying that, the cake was still a hit, and by the next evening, there wasn't a crumb left (just a few pieces of fondant).

Rainbow Cake

Adapted from sweetapolita

(Makes 6 thin 9 inch layers of cake)

220 grams butter, room temperature
450 grams of sugar
5 egg whites, room temperature
2 teaspoons vanilla
375 grams plain flour
4 teaspoons baking powder
½ tsp salt
250 grams of milk, warmed for 30 seconds in the microwave to bring to room temperature

Red, orange, yellow, green, blue and purple GEL food coloring, if you can.*

Preheat the oven to 175°C (350°F). Grease and line with baking paper how ever many 9” cake pans you have - I had two and kept alternating between the two.

In a bowl, sift together the flour, baking powder and salt. 

Beat together the sugar and butter until smooth, then add the egg whites, adding them a little at a time. Add the vanilla and mix until fully incorporated. Then, alternating between wet and dry, add the milk and flour mixture in two parts (I found that I had too much milk, and didn't use all of it. Use your judgement to see if you need more or less milk.)

Divide the batter amongst 6 bowls (I did it by weight. Weigh your mixing bowl before you begin adding ingredients and then subtract the weight of the bowl from the final measurement after the batter is completed. Divide that number by six and add that weight of batter to each bowl), and then mix a fair amount of the appropriate food color into each bowl, keeping in mind that the color of the unbaked batter will be the color of the baked batter. Pour into the pans and bake for 15 minutes each.

When you remove them from the oven, let them rest on the cooling rack, in the pan, for ten minutes. Then flip on to the cooling rack to cool completely before using - or into the fridge to cool quickly.

*I couldn't find purple and orange food colouring, so I mixed red and blue for purple, and red and yellow for orange.

Classic Vanilla Buttercream Frosting

 (makes enough to cover the cake and layers)

450 grams of unsalted butter, softened
6-7 cups of icing sugar
1/2 teaspoon salt

2 tablespoons vanilla extract

8 tablespoons of milk or cream

In a standing mixer fitted with a whisk, mix together 6 cups of sugar and butter (I cover mine with a clean towel to avoid the sugar blowing up everywhere - this doesn't stop it completely, but does control it a lot). Mix on low speed until well blended then increase mixer speed to medium and add vanilla extract, salt, and 4 tablespoons of milk/cream and beat for 5 minutes. If your frosting needs a more stiff consistency, add the remaining cup of sugar. If your frosting needs to be thinned out, add remaining milk/cream 1 tablespoon at a time.

To assemble the cake, place the first layer of cake on the cake board/serving plate, and cover with icing, then add the next layer of cake and repeat until you have built your cake tower. Cover the whole cake with icing and voila!

If you want to cover with fondant - use at your own risk!