orange, green and purple gel food colourings
150²µ/5Β½΄Η³ϊ caster sugar
coloured writing icing
ΒΌ 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