To make the honeycomb, lightly oil a 20cm cake tin. Put the sugar and syrup in a heavy-based pan over medium-low heat. Swirl the pan to dissolve the sugar, then stir with a spatula until all dissolved – this might take 10-15 minutes, so be patient and do not let the mixture bubble at this stage. Turn up the heat, use a sugar thermometer if you have one, and heat the mixture to 155C or until a dark amber caramel. Remove from the heat and quickly stir in the bicarbonate of soda until golden and foaming. Be careful not to over-stir: you want to retain as much air in the mixture as possible.

Carefully pour into the tin. Leave to harden and cool for about 90 minutes. Break into chunks and crush with a rolling pin.

If you are making the honeycomb butter, you will need half the amount, so store the rest in an airtight container at room temperature for up to 2 weeks. You can dip chunks in melted chocolate, sprinkle over ice-cream or make double the amount of butter and freeze.