Popcorn puffs up when heated because its kernels have a moisture-sealed hull and a dense, starchy interior. As this inner core gets hot the pressure builds and literally bursts through the exterior in a mini explosion. You can enjoy popcorn with no flavourings or with a little salt. Using a hot-air popcorn machine with make it even more healthy! However, all you really need is a large pan with a lid. Pour a thin film of oil into the pan add the kernels (a single layer) with sprinkle with salt and spices. Gently heat until it all pops, giving it a shake occasionally (hold on to the lid!). Once you’ve gone for 10 seconds without hearing any popping, take off the heat. Leave to stand with the lid on to avoid hot popcorn flying around your kitchen.