Place a double layer of cling film into an 8x8 inch square pan and spray with cooking spray.
Break up the biscuits and meringue nests into a large bowl and then add the dried fruit and nuts (if using).
Place the butter, golden syrup, milk and dark chocolate into a medium sized saucepan and place over a low heat. Stir frequently until everything is melted. Be careful not to scorch or boil the chocolate. Once you see there are a few tiny lumps left, remove from heat and continue to stir until everything is melted.
Pour the chocolate mixture into your biscuit mix and stir until all the biscuit mixture is covered in chocolate.
Tip the whole mixture into your prepared pan and squish into an even layer with a wooden spoon/spatula.
Place in the fridge for at least 2 hours, you can also leave it overnight. Once set, gently lift the fridge cake out of the pan and peel the cling film off. Place on a cutting board, dust with cocoa powder, if desired and slice into 9-12 squares.
Chocolate Fridge Cake will keep in an airtight container, in the fridge, for a week.