The primary ingredient in pineapple upside-down cake is pineapple. This classic dessert features a rich, buttery cake base topped with caramelized pineapple slices and often maraschino cherries. The pineapple is typically placed at the bottom of the cake pan before being covered with the batter. Once baked, the cake is inverted to reveal the sweet, sticky pineapple topping. The cake’s flavor is complemented by brown sugar and butter, which create a delightful glaze. This dessert is popular at potlucks and gatherings due to its appealing presentation and delicious taste.