3 x 340g packets White Wings golden buttercake mix
180g soft unsalted butter
1kg pure icing sugar
Red, blue, yellow and green food colouring
250g unsalted butter
Tip: Fondant, also known as white icing, is available from supermarkets. Decorating wires and fondant can be found at cake decorating suppliers.
Preheat oven to 160°C. Grease and line a 26cm round tin with baking paper. Make 3 x 340g packets White Wings golden buttercake mixes in the large bowl of an electric mixer, according to packet directions, with 6 eggs, 180g soft unsalted butter and 2¼ cups milk. Spread into prepared tin and bake for 1 hour 45 minutes or until a skewer inserted in the centre of the cake comes out clean. Allow to cool overnight.
To make the decorations, cut 1kg of fondant into four even 250g pieces. Knead each piece until smooth and pliable; if it sticks, lightly dust the surface with icing sugar. Colour each piece of fondant with food colouring (we used red, blue, yellow and green) and knead separately until coloured evenly. Cover with plastic wrap
Roll out one colour at a time until 3mm thick. Use a 1cm, 2cm, 3cm and 4cm round cutter to cut out rounds. Roll remaining fondant into balls for the side of cake. Set aside overnight to dry.
To make frosting, put 250g unsalted butter at room temperature, cubed, in the large bowl of an electric mixer and beat until pale and creamy. Add 2 tablespoons milk then 4 cups sifted pure icing sugar, large spoonfuls at a time, beating until mixture is smooth. Add 3 drops of food colouring (we used green) and beat until colour is pale.
Invert the cake onto a 32cm cake board so the bottom of cake is facing up – trim cake if it's not sitting flat. Spread frosting evenly over cake. Decorate cake with polka dots and balls around base.