An upside-down pineapple is a pineapple fruit that has been flipped over so that the leafy crown is facing downwards. This distinctive presentation is often used in culinary preparations such as pineapple upside-down cake, where the fruit is caramelized with butter and sugar before being placed at the bottom of the cake pan and topped with batter. The resulting dessert features a golden, caramelized pineapple layer on top once it's flipped out of the pan, creating a delicious and visually appealing treat.