Boil together the sugar, condensed milk and butter for a few minutes until the butter dissolves and the mixture begins to come away from the sides of the pan.
Add the chocolate off the heat and stir until completely dissolved.
Pour out into a pre lined/greased container.
Refrigerate for a few hours or freeze for 30mins.
Put you knife under boiling hot water, wipe the knife with a tea towel and cut into perfect cubes. It'll give you sharp meat edges a little trick from a professional chef.
