4 large oranges, zest only
1 large orange, juice only
gel food colouring in green, orange, red and yellow
5 tbsp golden syrup
330驳/11陆辞锄 plain flour, plus extra for kneading
6 tsp baking powder
135g/5oz caster sugar
75驳/2陆辞锄 cocoa powder
75驳/2陆辞锄 cornflour
600g/1lb 5oz royal icing sugar
165g/5戮oz unsalted butter, softened