Citrus Sunset Cake

Decorated with watercolor-inspired frosting, this lemon curd-filled cake is beyond beautiful.


  • Cake
  • 858 grams all-purpose flour
  • 530 grams caster (superfine) sugar
  • 1 teaspoon salt
  • 6 teaspoons baking powder
  • 750 milliliters of milk
  • 250 milliliters vegetable oil
  • 250 grams unsalted butter, softened
  • 4 tablespoons Greek yogurt (can substitute with sour cream)
  • 2 teaspoons vanilla extract
  • 4 large eggs
  • Zest of 1 orange
  • Zest of 1 lime
  • 400 grams lemon curd
  • Frosting
  • 1 kilogram softened unsalted butter (room temperature)
  • 1.5 kilograms soft icing sugar mixture (sifted after it's weighed)
  • 4 tablespoons milk (room temperature)
  • 2 teaspoons vanilla extract
  • 3 drops yellow food dye + 1 tablespoon lemon curd
  • 3 drops pink food dye + 1 tablespoon lemon curd
  • 3 drops orange food dye + 1 tablespoon lemon curd
  • 3 drops red food dye + 1 tablespoon lemon curd
  • 3 drops purple food dye + 1 tablespoon lemon curd


  1. Frosting
  2. Please note: You may need to make the frosting in two batches unless you have a large mixing bowl. Frosting can be made with a hand mixer or stand mixer
  3. Use a stand mixer or hand mixer to soften butter in a large bowl and mix for 5 minutes so it gains some volume and goes pale in colour.
  4. Add half the icing sugar mixture and mix until it's mixed into the butter, then add the rest of the icing sugar along with 2 tablespoons of milk and a tablespoon of vanilla extract.
  5. Cake batter
  6. Please note: You may need to make the batter in two batches unless you have a large mixing bowl. Batter can be made with a hand mixer or stand mixer.
  7. Preheat a fan-forced oven to 160C (320F) or 180C (356F) for a conventional oven. Line x 3 8 inch cake tins with baking paper. Set aside
  8. In the bowl of a stand mixer fitted with the paddle attachment, add the flour, baking powder, caster sugar and salt. Turn mixer on low speed and allow it to mix for a couple minutes to help everything combine well (alternatively you may do this by sifting the ingredients together). Add the softened butter and let it mix until it resembles a fine sand like texture.
  9. Next, add milk, eggs, yogurt, oil and vanilla extract in a large jug and whisk well.
  10. Add wet ingredients to dry ingredients in a slow and steady stream until no dry ingredients are visible. Scrape down the bowl, add lime and orange zest, and mix for another 20 seconds.
  11. Evenly divide batter amongst three cake tins. Bake for 40 min or until a toothpick inserted comes out clean. Allow them to cool completely on a wire cooling rack before frosting.
  12. Trim the tops of the cooled cake off using a large serrated knife. Discard the tops.
  13. Fit the end of a piping bag with a large round tip and add a little dab of frosting on an 8' a cake board. Place first layer of cake on top and press firmly to help it stick to the cake board.
  14. Frost a perimeter of frosting around the outside of the top of the cake layer. Add 1/2 lemon curd and use an offset spatula to spread on cake layer, ensuring it's spread evenly.
  15. Repeat with second layer.
  16. Use the piping bag to frost an even layer of buttercream all around the cake including the sides and top. Use a large offset spatula to spread the frosting around evenly taking care to ensure the sides of the cake are straight. It doesn't have to be perfect. This is only the crumb coat which helps lock in the cake crumbs so they don't appear in the second coating of buttercream.
  17. To colour the frosting split the rest into 5 separate mixing bowls Add 1 tablespoon lemon curd to each one and add food gel colouring. Mix until well combined. Transfer each colour to a separate piping bag.
  18. Start by piping a 2 inch high layer of the yellow buttercream to the bottom of the cake working your way up the cake with the pink, orange, red and lastly purple. You'll also need to pipe purple on top of the cake. Use a small offset spatula to spread evenly across the cake carefully and roughly blending the colours a little ensuring they don't mix too much.