Soft serve is a type of ice cream dispensed directly from a machine at a warmer temperature and with more air incorporated than churned, hard-packed ice cream, giving it a lighter, fluffier texture. The continuous-freezer technology behind it was developed in the U.S. in the 1930s, generally credited to Tom Carvel and to J.F. McCullough of Dairy Queen.
The base mix is similar to regular ice cream, milk, cream, sugar, and flavoring, but it's churned at higher speed and served straight from the machine rather than hardened afterward in a freezer. It's typically dispensed into a cone or cup, often in a swirl, and can be flavored or topped with syrups, sprinkles, and mix-ins.
Soft serve is a fixture at fast-food chains, fairs, and amusement parks in the U.S., and has developed distinct regional forms elsewhere, such as matcha and sakura flavors in Japan.