½ cup water

175g butter, chopped

450g Chelsea Caster Sugar

75g sweetened condensed milk

Lightly grease a 20cm square tin or slice tin and line with baking paper.

In a large pot, bring the water to a simmer. Add the butter, stirring until melted. Add the sugar, stirring continuously until dissolved. Whisk in the condensed milk. Cook on a gentle simmer, stirring continuously for 20 minutes until the mixture becomes pale golden in colour and thickens. To test it is ready, drop a little of the mixture onto a saucer, it shouldn’t run and should be thick after 30 seconds or so.

Remove the pan from the heat and beat the mixture for a good 10 minutes with a wooden spoon until thick.

Spoon the mixture into the tin and smooth the top. Allow to stand for 1 hour, or until set. It is best left overnight.

Remove from the tin, trim the edges and cut into 5x5 or 5x4 squares. Keep in an airtight container.