Frozen custard

Frozen custard is a frozen dessert that is a type of ice cream that is made with egg yolks in addition to cream and sweetener, either sugar or an alternative, and an additional flavoring such as cocoa, vanilla, or fruit such as strawberries or peaches. It is usually kept at a warmer temperature compared to ice cream, and typically has a denser consistency. Egg yolks have been integrated into ice creams since at least the 1690s, though there are several notable invention stories that are associated with modern commercializations of this practice. One early commercialization of frozen custard was in Coney Island, New York, in 1919, when ice cream vendors Archie and Elton Kohr found that adding egg yolks to ice cream created a smoother texture and helped the ice cream stay cold longer. In their first weekend on the boardwalk, they sold 18,460 cones.

Source: Wikipedia