- 45 min + chilling
- 50 min
- 400g butter, softened
- 1 tbsp Queen Madagascan Vanilla Bean Paste
- 2 cups (440g) caster sugar
- 4 cups (600g) plain flour, sifted
- 6 sachets Dr. Oetker Baking Powder
- 1 ½ cups (375ml) milk
- 6 large eggs
- Queen Food Colour Gel or Liquid in Red, Blue, Green & Yellow
Swiss Meringue Buttercream
- 300g pasteurised egg white from carton
- 2 1/4 cups (500g) caster sugar
- 500g butter, slightly softened
- 3-4 tsp Queen Bubble Gum Flavour for Icing
- Dr. Oetker Polka Dots
- Dr. Oetker Sour Strands
- Dr. Oetker Hundreds & Thousands
Method - Cake
Preheat oven to 180 degrees C, grease and line 2 x 20cm round cake tins.
Combine butter, vanilla, sugar, milk, eggs, sifted flour and Baking Powder in the bowl of a stand mixer. Mix on low until all combined, then increase to high, beating until light and well mixed.
Divide mixture evenly into six bowls using a scale or half cup measure. Use Food Colour Gels to create desired rainbow colours in Red, Orange, Yellow, Blue, Green, Purple.
Add bowls 1-3 into one cake tin and use the end of a spoon to gently marble colours. Repeat in the second tin with bowls 4-6. Bake for 45-50 minutes or until an inserted skewer comes out clean. Allow to cool for 15 minutes before turning out onto a cake rack to cool completely.
Method - Swiss Meringue Buttercream
Prepare buttercream by dicing butter into 2cm pieces, set aside. Combine egg whites and caster sugar in a large bowl and sit over a saucepan of just simmering water. Whisk continuously until mixture is hot to touch and sugar dissolves.
Transfer mixture to a stand mixer with a whisk attachment fitted. Whisk for 5-10 minutes until a thick glossy meringue forms with stiff peaks and the mixture has cooled down.
Switch to a paddle attachment, and on medium speed, add butter a little at a time, allowing it to incorporate fully before adding more. Add Bubble Gum Flavour to taste. Increase speed to high and beat for 5 minutes until a thick buttercream forms.
Method - Assemble
To assemble, cut cake in half horizontally using a large bread knife. To create two even layers, make small cuts while turning the cake. Place one blue-green marble layer on a cake stand and top with a cup of buttercream. Smooth with a spatula then top with the second blue-green cake. Repeat, following with red-orange cakes.
Add a thick and even coat of buttercream around the top and sides of the cake, then chill for 15 minutes to set slightly. Use a large French star tip to pipe a border around the top and bottom of the cake, and sprinkle Polka Dots, Hundreds & Thousands and Sour Sugar Strands. Time to party!