Grease a slice tin and line with baking paper.
Place all ingredients apart from the bicarb soda into a medium sized saucepan.
Stir over very low heat until sugar dissolves.
If you have a candy thermometer, place it in the mixture.
Increase heat slightly to low or low-medium until mixture boils. It should boil at a medium pace. Decrease temperature if it starts boiling too fast.
Boil, stirring from time to time, until the mixture reaches 155 degrees celsius (310 degrees fahrenheit) OR - if you don't have a thermometer - until it reaches a rich golden colour. The process should take about 10 minutes, but will depend on your stovetop and various factors.
Remove from heat and sprinkle the bicarb soda over the top of the mixture. Stir gently until the mixture starts to froth and continue stirring gently until all of the mixture is frothy. Don't stir too quickly or for too long or the mixture will lose its frothiness.
Pour into slice tin and allow to cool.
Once cool, break into pieces. Drizzle or dip in chocolate to serve.