Whenever I visit the cinema, I ask for a mixture of sweet and salty popcorn in one big box. Here that classic combo gains an extra depth of flavour from umami-rich nori and toasted sesame seeds, while soft brown sugar lends the popcorn a sweetness not dissimilar to that of the crispy seaweed you can get in Chinese restaurants.
The addition of melted butter makes this a slightly less virtuous snack but it is particularly delicious, with the added bonus of helping the seasoning to coat each piece of popped corn. Omit the butter, if you prefer.