• Preheat oven to 170 degrees celsius (fan-forced).
• Grease two round tins and line the bottom of the tins with baking paper.
• Beat eggs and sugar on medium-high in a stand mixer for 5 minutes or until pale and fluffy. Add golden syrup gradually and beat to combine.
• Sift arrowroot three times.
• Sift all dry ingredients into mixture, ⅓ at a time, folding with a spatula to combine.
• Pour an equal amount of mixture into the two prepared tins.
• Bake for 20 minutes.
• Allow to cool for 5-10 minutes before gently easing each cake from its tin. Allow to cool completely before decorating.

Filling and icing

• Beat butter and sugar in a stand mixer on med-high for 5 minutes.
• Lower speed and add cocoa and milk gradually. Return to med-high speed for a couple of minutes.
• Lower speed and add boiling water gradually. Return to med-high speed for a couple of minutes or until creamed.
• Use cream as a middle filling in the sponger and to ice the top of the sponge.
• Decorate with sliced oranges.