bicarbonate of soda
- Place sugar, golden syrup, vinegar and butter in a heavy-based saucepan and cook over a medium heat, stirring, until sugar dissolves.
- Increase heat and boil, without stirring, until mixture reaches the hard crack stage (When the syrup is dropped into iced water it separates into threads which become hard and brittle)or 150 degrees C on a sugar thermometer.
- Remove pan from heat, stir in bicarbonate of soda and continue stirring until mixture swells.
- Pour into a lightly oiled 23 cm square cake tin and when almost set, cut into squares.