Butter an 18cm square or 10x20cm tin

Add the water and butter to a large saucepan and heat until the butter has melted

Add the sugar and dissolve it, then turn the heat up high bringing it to a hard boil. Stir continuously to avoid burning

Slowly add the condensed milk - be very careful of it spitting back - stir it in the lower the heat to a simmer

The mixture will resemble the surface of the moon by now! It should be bubbling and darkening in colour

When visibily thickened, around 20 minutes of simmering, remove the pan from the heat and beat the mixture vigorously until smooth. You can add flavouring at this point if you wish - vanilla, peppermint, whiskey etc

Pour mixture into the buttered tin. Let cool enough to cut it before it cools completely.

Store in an airtight container

This is very sweet...lol