Butter the base and sides of a 20cm non-stick square cake tin. (If your tin isn’t non-stick, butter, then line with baking parchment).

Melt the sugar and golden syrup in a deep saucepan over a low heat, stirring. Don’t let it bubble until the sugar has dissolved completely.

Once melted, turn up the heat and bring to a simmer. Cook until you have an amber-coloured caramel (this won’t take long, but if you have a thermometer, it needs to reach 150C, so it doesn’t get sticky when stored). As quickly as you can, remove from the heat, add the bicarb and beat with a wooden spoon until it’s all absorbed and the mixture is foaming. Immediately scrape into the tin, but be careful, as the mixture will be very hot.

Leave to cool for 1-1 1/2 hrs until the honeycomb is hard – it will continue bubbling in the tin as it cools. Break into chunks before packaging.