Make this in a room with less than 40% RH.
Heat 75 g soft light brown sugar, 200 g caster sugar, 75 g golden syrup, 25 g unsalted butter and a pinch of salt to 160°c. Whisk in 1 teaspoon bicarbonate of soda, then 175 g shelled and skinned peanuts, cashews, hazelnuts or macadamia nuts (or all) and immediately pour onto a cold surface such as a baking sheet that has been in the freezer.
Try and flatten with a wooden spoon so the pile is not too tall.
Allow to cool, smash up into smaller pieces and store in an air sealed container.