The primary ingredient in a pineapple upside-down cake is, unsurprisingly, pineapple. Traditionally, this cake is made by arranging slices of pineapple (often canned, but fresh can also be used) at the bottom of a cake pan, usually with maraschino cherries in between. A buttery brown sugar mixture is often poured over the pineapples before the cake batter is added on top. As the cake bakes, the pineapple caramelizes and becomes syrupy, creating a sweet and moist topping when the cake is inverted before serving. This cake is a beloved classic, often enjoyed at picnics and gatherings.