Kettle corn is a form of popcorn which is made with both salt and a sweetener, creating a very distinctive flavor. This dish originated in Colonial America, where it became quite popular, and it spread to some parts of Europe, especially Germany. Kettle corn actually briefly fell out of favor in the United States before experiencing a resurgence in the late 20th century, perhaps as part of an overall renewed interest in traditional American foods. Kettle corn can be found at many fairs and social events, and it can also be made at home, either from scratch or from popcorn making kits.
Popcorn is an ancient New World treat. Archaeological expeditions have uncovered the traces of popcorn popping in settlements which are thousands of years old, suggesting that Native Americans were quite familiar with the properties of popping corn. When colonists first reached the Americas, they were undoubtedly introduced to popcorn at a fairly early stage, and by all accounts it was a very popular novelty food, which was also served as a snack at theater and music performances.
The original kettle corn appears to have emerged in the early 1700s, probably among Dutch settlers in New England. Their take on popcorn quickly spread, and it became a popular dish. Early kettle corn would not have used sugar, because it was an extremely expensive and rare sweetener. Honey and molasses are more likely candidates, and it was probably also cooked in lard, rather than vegetable oil, but the flavor would have been remarkably similar to that of modern kettle corn.
This popcorn product is not sweet, despite the addition of sugar. It has a distinctive salty, tangy flavor thanks to the blend of sugar and salt, and when well prepared it is not very greasy, because minimal amounts of oil are used. It is made by combining popping corn, oil, salt, and sugar in a large kettle and heating it slowly, tossing it to coat the popcorn in sugar, salt, and oil as it pops.
Many farmers' markets, flea markets, and other large fairs offer kettle corn. In some areas, people dress up in period costumes to make kettle corn, making the cooking process an event, and the kettle corn is served in bags for easy transport and so that people can take leftovers home. Some companies offer to ship kettle corn as well. If you want to make kettle corn from scratch at home, you will need a large heavy pot and a stable heat source. Heat a small amount of oil in the bottom of the pot, and then add popping corn, sugar, and salt. Keep a lid on the pot so that the popcorn does not escape, and shake it as the corn pops to ensure even distribution; when you're finished, adjust the seasoning to taste, and enjoy or pack the kettle corn into airtight containers for storage.