Go Back
A tall slice of layered rainbow cake with green, yellow, orange, and pink layers, frosted with white icing and topped with fresh strawberries, set against a plain white background.
Print

Four Citrus Layer Cake

Ingredients

  • 1 stick butter at room temperature
  • 1/3 cup coconut oil
  • 8 oz sugar 1 cup plus 1/8 cup
  • 1 1/8 tsp baking powder
  • 1 1/4 tsp baking soda
  • heaped 1/4 tsp salt
  • 4 egg whites
  • 1/2 Tablespoon of vanilla
  • 1 cup buttermilk
  • 2 cups cake flour
  • zest of half a blood orange plus 1 tablespoon juice from the blood orange
  • zest of a half a lemon plus 1 tablespoon juice from the lemon
  • zest of 1 lime plus 1/2 tablespoon juice from the lime
  • zest of half a grapefruit plus 1 tablespoon juice from the grapefruit
  • gel food coloring green, yellow, pink, and a dark red

Instructions

  • Begin by making the buttercream and lemon curd. These can be made hours or even days ahead of time and stored in the fridge. If they are in the fridge, you'll need your buttercream to come to room temperature and to fluff it again before you use it. Next, make the cakes:
  • Preheat oven to 325, butter and flour two 5 inch cake pans.
  • In the bowl of a stand-mixer combine butter, coconut oil, sugar, baking powder, baking soda, and salt (you can also use a hand mixer). Mix on low speed to moisten then increase to medium and cream until light and fluffy (scrape your bowl halfway).
  • Add egg whites one at a time while mixer is running. Add vanilla and combine.
  • Reduce the speed to low and add the cake flour and buttermilk in halves, alternating between them.
  • Once smooth, mix with a spatula or spoon to ensure the ingredients on the bottom are combined.
  • Divide your batter into four bowls. Into the first bowl add the lime and its zest, and just enough green food coloring to make a pale color. Into the second, add the lemon juice and zest (if the batter looks yellow enough, leave it as is - otherwise use a tad yellow coloring to turn it yellow). Bake your first two cakes for 25 - 30 minutes, checking at 25 minutes for doneness.
  • To the third bowl add the grapefruit zest and juice, add some pink color and a drop or two of yellow to get as close as possible to the grapefruit color. To the fourth, add the blood orange zest and juice. The blood orange lends itself to a lovely color alone but should you wish to deepen it, use the red and pink to get you closer to the real color.
  • Once your first two cakes come out, let them cool for 5 minutes then remove and place on cooling rack. Wash the pans, dry them and butter and flour them. Bake your last two cakes the same way.
  • Once all your cakes are done and cool, trim the domes off with a bread knife. Begin layering with the green on the bottom (bottom down), and using a piping bag, pipe a circle border around the edge of the cake. Fill with lemon curd. On top, place your lemon cake face down. Repeat process until you have the blood orange on top, face down. Frost the whole cake with buttercream