1.Grease a 20cm square cake pan. Line the base and sides with baking paper, extending paper 5cm over the sides.
2.Combine the cranberries, pistachios, coconut and marshmallows in a large bowl.
3.Melt the chocolate in a large heatproof bowl over a pan of simmering water; do not allow the bowl to touch the water.
4.Add the marshmallow mixture to the chocolate; mix well. Spoon the mixture into the prepared pan; press in firmly. Refrigerate for about 1 hour or until set.
5.Remove rocky road from the pan; cut into 20 pieces. Store in an airtight container in the refrigerator.