Melt the butter in a large pan over a low heat.
When it's about half melted, add the dark chocolate, the milk chocolate.and the golden syrup.Over a very low heat, continue to melt it all. Stir until it's thick and well combined.
Remove from the heat and set aside for 10 minutes until it's cooled slightly.
Add the mini Creme Eggs, the marshmallows and the digestive biscuits, stir until everything is well coated.
Line a 20cm x 20cm baking tin with baking paper and press the mixture firmly in.
Meanwhile melt the white chocolate in a bowl over a saucepan of steaming water. Make sure you keep the temperature very low as white chocolate can seize easily.
Take half of the melted chocolate and put in another small bowl, colour until very deep yellow using the gel food colour, just a very small amount at a time.
Drizzle the white chocolate and the coloured white chocolate over the rocky road, cut the full size Creme Eggs in half and sit in the chocolate, pressing in firmly.
Allow to set in the fridge for at least a couple of hours.
Turn out of the tin and cut into small chunks using a very sharp knife.