Put the caster sugar, golden syrup, clotted cream, vanilla and a pinch of sea salt flakes in a slow cooker. Stir until well-mixed and smooth. Cook on high for 4-5 hrs, stirring every 30 mins, or until it’s a golden caramel colour and looks glossy. If your slow cooker works with the lid off, cook uncovered to speed up cooking. It will take about 5 hrs if using a multi-function cooker with a locked lid that requires you to keep opening and stirring it.

Oil a 20cm baking tin and line with baking parchment. Remove the bowl of the slow cooker carefully and set on a heatproof mat or chopping board. Mix with a wooden spoon or spatula vigorously for 10-15 mins to cool the fudge and to break up any large sugar crystals. The fudge will thicken as it cools and start to look matte. Tip into the tin and use a spatula to smooth the surface. Sprinkle with a little more salt and chill until set, about 1 hr. Cut into chunks. Will keep for five days in an airtight container.