4 large oranges, zest only
1 large orange, juice only
gel food colouring in green, orange, red and yellow
5 tbsp golden syrup
330²µ/11½´Ç³ú plain flour, plus extra for kneading
6 tsp baking powder
135g/5oz caster sugar
75²µ/2½´Ç³ú cocoa powder
75²µ/2½´Ç³ú cornflour
600g/1lb 5oz royal icing sugar
165g/5¾oz unsalted butter, softened