( SERVES 36 )
1. Grease a 20cm cake tin. Place all ingredients, except vanilla, in a large, heavy-based saucepan over a gentle heat. Warm, stirring until the sugar has dissolved. Bring to the boil, then turn down the heat to simmer for about 20 minutes or until the mixture reaches the soft-ball stage.
2. Remove from the heat and stir in vanilla, then beat with an electric mixer until thick and creamy. Pour into prepared tin. Caramel fudge is easiest to cut into pieces when just set but still warm.
Tip: The soft-ball stage means that when a little of the mixture is dropped into a glass of cold water, the mixture will form a ball that is soft to touch (not hard like toffee). Another way to measure this is to use a specially designed sugar thermometer. When the sugar thermometer reaches 120°C, this is the correct temperature for the soft-ball stage.