Grease an 8 inch square baking pan with baking paper and set it aside.
In a large saucepan, over medium heat, slowly bring the sugar, cream and glucose to the boil, stirring constantly.
When boiling, cover and cook for 3 minutes on medium heat.
Uncover and then cook until it gets to 112C on a candy thermometer or the soft-ball stage (when a small amount of mixture dropped into very cold water forms into a ball which flattens on removal from water).
Stir in the butter and then cool without stirring until it is lukewarm, about 43C. This will take around 45 minutes.
Add the vanilla essence and the marshmallow fluff and beat with a wooden spoon until thickened.
Nutritional information is an estimate and provided as a courtesy. The values may vary according to the ingredients and tools that are used. Please use your preferred nutritional calculator for more detailed information.