Line an 18cm square tin with baking paper

Combine all the ingredients in a large saucepan and place over a medium heat. Cook for 15–20 minutes, stirring occasionally to stop the mixture from catching on the bottom of the pan

The fudge is ready when it reaches 116°C on a sugar thermometer

When the fudge reaches 116°C on a sugar thermometer remove from the heat. Leave to cool slightly before beating with a wooden spoon until the mixture turns from shiny to matte

Spread out in the lined tin and cover with baking paper. Transfer to the fridge for 1 hour to set before cutting in to squares to serve