Rainbow Cake
 
Prep time
Cook time
Total time
 
Author:
Serves: 12-14
Ingredients
  • for 5 layers of cake (I doubled these ingredients)
  • 2¾ cups all-purpose flour
  • 1 tsp baking soda
  • ½ tsp salt
  • 2 cups granulated sugar
  • 170 grams unsalted butter, softened
  • ¼ cup vegetable oil
  • 3 large eggs
  • 2 large egg yolks
  • 1⅓ cups buttermilk
  • 1 tbsp vanilla extract
  • 1 tsp vinegar
  • food coloring ( you really need just red, blue and yellow to make all the colors)
  • buttercream frosting, this is for 7-8 layers
  • 675 grams butter, softened
  • 8-9 cups confectioners sugar, sifted
  • 1 tsp salt
  • 3 tbsps vanilla extract
  • 9-10 tbsps heavy cream
Instructions
  1. To prepare the buttercream, beat butter 5 minutes with a mixer (I use a hand held one). Add around 7 cups of powdered sugar and mix on the lowest speed (so the sugar doesn't blow everywhere) until the sugar is fully incorporated with the butter. Increase mixer speed to medium and add vanilla extract, salt, and 7-8 tablespoons of cream and beat for another few minutes. If your frosting needs a more stiff consistency, add remaining sugar. If your frosting needs to be thinned out, add remaining cream 1 tablespoon at a time.
  2. To prepare the cake layers, preheat oven to 350°F/175°C. Butter and flour 7-inch round baking pans. Set aside.
  3. In a mixing bowl add flour, baking soda and salt. Sift in cocoa powder then mix mixture 20 seconds, set aside.
  4. In another bowl whip together sugar and butter until pale and fluffy. Mix in vegetable oil. Blend in the eggs one at a time, mixing just until combined after each addition. Mix in egg yolks.
  5. In a pan whisk the buttermilk with the vanilla extract and vinegar. Working in three separate, beginning and ending with flour mixture, add ⅓ of the flour mixture alternating with ½ of the buttermilk mixture and mixing just until combined after each addition. Scrape down sides and bottom of bowl with a rubber spatula to ensure everything is incorporated.
  6. Divide mixture evenly first in bowls so you can mix the color. Make a color of your choice, in this case it was red, orange, yellow, light green, dark green, blue, and purple. Once you have mixed in the colors to your satisfaction, pour into the prepared baking pans. I did 300 grams of each color separately and it worked out just right. If you want thinner layers you could do a little less.
  7. Even out the batter in your pan and bake in the preheated oven for 25 - 30 minutes or until toothpick inserted into center of cake comes out clean. Cool in cake pan, invert onto wire racks to cool completely. Once cool, you slice of the top if it is domed.
  8. To put the cake together, place the first layer of cake (according to the color scheme you have chosen), on a cake stand. Spread a thin layer of the frosting on (in my case it was around a cup). Place the next layer on top and repeat with all the layers.
  9. Frost the cake on the outside, putting a thin layer all around. I don't have a rotating stand so this was difficult to do with such a tall cake and even though I wanted a cake that was just smooth, I totally messed up! If this happens decorate with frill, swirls, whatever you like! :)
Recipe by Box of Spice at https://boxofspice.com/2015/09/rainbow-cake/