National Lemon Chiffon Cake Day is observed worldwide every March 29, celebrating the light and fluffy dessert known as chiffon cake, particularly in its lemon flavor. The chiffon cake was invented in 1927 by Harry Baker, who initially created it for the Brown Derby restaurant in Los Angeles and kept the recipe secret for two decades before selling it to General Mills. The cake gained popularity in the 1940s and 1950s, being marketed as a novel dessert, with the first recipe published in Better Homes and Gardens magazine. Chiffon cakes are characterized by their moist texture, achieved through the use of vegetable oil and beaten egg whites, and they can be flavored in various ways, including with lemon zest and juice. On this day, fans of the cake are encouraged to enjoy a slice, either homemade or from a bakery, and share their experience on social media using the hashtag #NationalLemonChiffonCakeDay.