Lightly grease a 27 x 17cm pan
Place sugar and water into a heavy saucepan. Stir over a low heat for 10 minutes until the sugar has dissolved.
Add the butter and syrup, stirring until the butter has melted. Add Nestlé Condensed Milk and bring to the boil, stirring continuously.
Cook gently, stirring all the time, for approximately 25 minutes until soft ball stage (test with a sugar C, or drop a little mixture into a cup of tap water - it is? thermometer -180 ready when the drop forms into a ball when rolled between the thumb and index finger).
Remove from the stove, add the vanilla essence and beat until it begins to thicken.
Pour into pan and leave to cool. Cut into squares when almost cold.