Bonfire Night Toffee

450g/1lb Demerara sugar

125g/4oz butter

125/4oz treacle

1 tablespoon vinegar

1 tablespoon water

1 tablespoon milk

Put all the ingredients except the vinegar into a saucepan and gently bring to the boil, stirring well all the time. Keep boiling gently for fifteen to twenty minutes, still stirring to prevent burning, until a test drop of the mixture becomes brittle when dripped into a cup of cold water. Now stir in the vinegar and pour into well-greased shallow tins. When nearly set, score deeply with a knife into conveniently sized squares.