Book & Recipe: “Pie in the Sky” Rainbow Cake

The book is about an 11 year old boy who is an immigrant. Learning the local language and customs prove challenging, and even harder because his younger brother is adapting readily. The two boys end up into big trouble in – you guessed it – the kitchen. The final and most important recipe is Rainbow Cake.

 

Zeke’s been begging to bake it since the moment we put the book down and mother’s day seemed like the perfect day for a mother son kitchen challenge. Ours didn’t turn out quite as beautifully as we’d hoped (cakes aren’t supposed to have craters in the middle!), but it sure tastes divine.  We’re glad we tried something new!

Here is the recipe:

• 24 oz (680 g) cake flour
• 24 oz (680 g) granulated sugar
• 1 tsp (1 tsp) salt
• 2 Tbsp (2 Tbsp) baking powder
• 1 tsp (1 tsp) baking soda
• 10 oz (283 g) egg whites room temperature
• 6 oz (170 g) vegetable oil
• 18 oz (510 g) buttermilk room temperature or slightly warm
• 12 oz (340 g) butter unsalted and softened
• 1 Tablespoon (1 Tablespoon) vanilla extract

• 1 stick butter 
• 6 tablespoons buttermilk 
• 1. Box powdered sugar 

NOTE: It is SUPER IMPORTANT that all the room temperature ingredients listed above are room temperature and measured by weight so that the ingredients mix and incorporate correctly. 
Heat oven to 335º F/168º C 
Prepare six ( 8"x2") cake pans with cake goop and place a round piece of parchment paper in the bottom of the pan for easy removal of the cake
Combine 8 oz of the buttermilk and the oil together and set aside. 
Combine the remaining buttermilk, egg whites, and vanilla together, whisk to break up the eggs and set aside. 
Combine flour, sugar, baking powder, baking soda and salt in the bowl of a stand mixer with the paddle attachment. Mix 10 seconds to combine. 
Add your softened butter to the dry ingredients and mix on low until mixture resembles coarse sand (about 30 seconds). 
Add in your milk/oil mixture and let mix until dry ingredients are moistened and then bump up to med (setting 4 on my KitchenAid) and let mix for 2 full minutes to develop the cake's structure. If you don't let your cake mix on this step your cake could collapse. 
Scrape your bowl and then reduce speed to low. Add in your egg white/milk mixture in three batches, letting the batter mix for 15 seconds between additions. Scrape down the sides again to make sure everything has incorporated.
Divide your batter into 6 bowls. Weigh 15 ounces of batter for each bowl.
Color each bowl with your Electric food colors. 1/2 tsp for pink for the pink layer, 1/4 tsp yellow plus 1/4 tsp orange for orange layer, 1/2 tsp yellow for yellow layer, 1/4 tsp yellow plus 1/2 tsp green for green layer, 1/2 tsp blue for blue layer, 1/4 tsp pink and 1/2 tsp purple for the purple layer. 
Bake your layers for 20-24 minutes or until the edges JUST start pulling away from the cake pan. Do not under-bake or the middle of the cake will collapse. 
IMMEDIATELY TAP PAN FIRMLY on countertop once to release the steam from the cake. This stops the cake from shrinking. 
Let cakes cool for 10 minutes inside the pan before flipping them out. The cake will shrink a bit and that is normal. 
Freeze your cake layers 30-60 minutes before trimming your cakes. Frost and fill with frosting.
For the frosting: melt butter in a sauce pan.  Add buttermilk and bring to a simmer.
Sift whole box of powdered sugar into a large bowl.
Pour butter and buttermilk over the powdered sugar and blend.  Icing will be somewhat loose.  If you desire more of a glaze, pour right over the cakes as you stack them. If you prefer a firmer frosting, refrigerate until the desired texture and then spread over each layer of cake.  If you want to surprise your guests, frost the sides, too! 
https://sugargeekshow.com/recipe/rainbow-cake/