Line a 20cm square baking tin with parchment paper. Leave some overhang for easy removal later.
Combine 200g dark chocolate, 100g milk chocolate, 125g unsalted butter, and 3 tbsp golden syrup in a heatproof bowl.
Melt the mixture over a pot of simmering water (double boiler method) or in the microwave in short bursts.
Stir until the mixture is smooth and fully melted.
Break 100g digestive biscuits into bite-sized pieces. Don’t worry about making them uniform; chunks are fine.
If using, roughly chop 100g mixed nuts.
Remove the melted chocolate mixture from the heat and let it cool slightly.
Stir in the broken biscuits, 100g mini marshmallows, 100g halved glacé cherries, and the chopped nuts.
Mix until all the ingredients are evenly coated with the chocolate.
Pour the chocolate mixture into the prepared baking tin.
Use the back of a spoon to press it down evenly, ensuring it’s level.
Place the tin in the fridge for at least 2 hours. Let the Rocky Road chill until it’s firm and set.
Once set, lift the Rocky Road out of the tin using the parchment overhang.
Cut it into squares or bars. For a decorative touch, dust with icing sugar before serving.
Store any leftover Rocky Road in an airtight container in the fridge. It will keep well for up to two weeks.