Line a large, shallow baking tray with greaseproof/parchment paper. You can grease the tray lightly to make the paper stick to it

Pour the sugar into a large, heavy-bottomed saucepan

Turn the stove on to a medium-low heat, add the water and stir for about 30 seconds until the sugar has turned to a thick syrup

Bring to the boil (still without stirring) allowing it to simmer for 5 minutes or, if you're using a candy thermometer, bring up to the hard crack stage of 146-154°C/295-309°F

Turn of the heat, stir in the butter quickly

Add the peanuts and stir in quickly

Add the bicarbonate of soda and stir in quickly

Pour carefully on to the prepared baking tray and allow to cool for about half and hour

Break up into pieces using a toffee hammer or butt of a kitchen knife

Store in an airtight container lined with greaseproof paper