Melt the butter, dark chocolate, milk chocolate, and golden syrup over a bain marie. Allow to cool for 5-10 minutes.
Stir in the digestives, marshmallows and mini creme eggs until everything is coated.
Transfer the mixture to a deep tray lined with baking paper.
Melt 75g of the white chocolate and stir in some of the yellow food colouring until the desired colour is reached. If it seizes on you, add a little bit of oil and stir it until it reaches a runny consistency again.
Drizzle over the rocky road mixture.
Melt the remaining white chocolate and drizzle that over too.
Cut the creme eggs in half and press firmly into the mixture.