A sundae is a type of ice cream. It is usually made by pouring a layer of syrup (chocolate, caramel, jam, etc.) on top of regular ice cream, sometimes with other toppings (dried fruit, fruit, etc.). KFC sundaes seem to have jam added.

This kind of ice cream originated in the late 19th century, and the place of origin varies, one of which is that after the city of Evanston, Illinois, passed an anti-soda law, the merchants in the city used syrup instead of soda in the ice cream soda, and so the sundae became popular.