1. Place the butter in a medium saucepan over low heat and melt completely.

2. Stir in the condensed milk, water, and soft brown sugar until the sugar has fully dissolved.

3. Increase the heat and bring the mixture to a boil, stirring continuously. Cook until it reaches the soft ball stage (115°C / 239°F). If you wish to add any flavourings (such as mince pie mix) now is the time.

4. Remove the pan from the heat. Using a wooden spoon, beat the mixture continuously as it cools. You can stir in any flavourings, such as mince pie filling mix, before the fudge begins to set. Continue until the mixture thickens and takes on a dull appearance.

5. Pour the mixture into a greased or lined metal tray and smooth the surface.

6. Allow the fudge to cool completely at room temperature before cutting into squares.