orange, green and purple gel food colourings
150²µ/5½´Ç³ú caster sugar
coloured writing icing
¼ tsp salt
175g/6oz self-raising flour
1 tsp vanilla extract
handful crisp-coated chocolates, such as Smarties
handful white chocolate chunks
85g/3oz unsalted butter, softened
1 free-range egg, beaten