This is a smooth fudge that hints of maple and the sharpness of orange.
Combine all the ingredients in a heavy saucepan.
Over a gentle heat, stir constantly until all the sugar has dissolved and the butter and chocolate have melted.
Bring the mixture to the boil and cook it to the soft ball stage, 116°C/240°F.
Remove the pan from the heat and dip its base in cold water to arrest further cooking.
Leave the mixture to cool to 43°C/110°F.
Beat the cooled syrup until it just thickens and lightens in colour.
Scrape the fudge into a buttered 20 cm/8 inch square tin.
Smooth over to level the surface.
Leave to set in a cool place.
When firm, cut the fudge into 2.5 cm/1 inch squares.