In a saucepan, melt the chocolate, butter and golden syrup together. Leave it to cool for a few minutes.
Place the digestive biscuits and pretzels into a large bowl then use your hands (or the end of a rolling pin) to crush them into medium-sized chunks. Stir in the marshmallows and popcorn.
Pour the melted chocolate mixture into the bowl and mix well until everything is evenly covered.
Transfer the mixture to your lined tin and press it down firmly into place.
Refrigerate for 3 hours or until firm then cut into bars and enjoy!
Video
Notes
Store in an airtight container for up to 2 weeks. Rocky road bars are best kept in the fridge.