Break the chocolate into pieces and melt in a microwave on half power for bursts of 30 seconds at a time.
Add the chopped dates, broken pecans and dried blueberries or raisins to the melted chocolate and mix well.
Place a sheet of non stick lining paper in the tin and pack the mixture into the tin. Flatten down the mixture using the back of a spoon to make sure it is well compacted.
Place in the fridge for about an hour to chill and set.
Cut into pieces using a sharp knife and store in an airtight container.