National Pineapple Upside-Down Cake Day is observed worldwide on April 20 every year, celebrating the delightful dessert known for its unique presentation. The origins of upside-down cakes can be traced back to the Middle Ages, but they gained popularity in the early 1900s, particularly after Jim Dole's invention of canned pineapples, which are essential for making the cake. The dish became even more popular following a 1926 advertising campaign by the Hawaiian Pineapple Company, which showcased the versatility of canned pineapples through a recipe contest that led to the publication of a cookbook featuring 100 winning recipes. To prepare a pineapple upside-down cake, bakers typically line the bottom of a pan with slices of canned pineapples, place a cherry in the center of each ring, sprinkle with butter and sugar, pour cake batter on top, and bake it. The cake is then inverted for serving, revealing its visually appealing design.