Key lime pie

Key lime pie is an American dessert pie made of Key lime juice, egg yolks, and sweetened condensed milk. It may be served with no topping, topped with a meringue topping made from the egg whites, or with whipped cream; it may be cooked in a pie crust, graham cracker crust, or no crust. The dish is named after the small Key limes, which are more aromatic than the common Persian limes, and which have yellow, not green, juice. The filling in a Key lime pie is also yellow, largely because of the egg yolks.

The filling is made by simply mixing the ingredients without cooking: the proteins of the egg yolks and condensed milk and the acidic lime juice curdle, thickening the mixture without baking. Today, key lime pies are usually baked to pasteurize the eggs and thicken the filling further.

The Key lime pie is probably a direct descendant of the Magic Lemon Cream Pie, invented in 1931 in the test kitchens of Borden, the leading producer of condensed milk, and attributed to their fictional spokesperson, Jane Ellison. A "Tropical Lime Chiffon Pie", using condensed milk and egg yolks, is documented in a 1933 Miami newspaper article. An "icebox lime pie", was mentioned as a specialty of the Florida Keys in 1935. and a recipe under the name "Key Lime Pie" was published in 1940.

No earlier solid sources are known, despite appeals to the public. A 1927 Key West Women's Club cookbook does not mention the recipe. A 1926 restaurant menu includes "lime pie", but it is unclear what it was. Various accounts claim that it was known earlier, but none were recorded before 1933. A widely-reported story claims that William Curry's cook Aunt Sally invented it in the late 19th century. But there is no evidence for this, and the oldest version of this story dates to only 1995, in promotional materials for a Bed and Breakfast in his old house.

It was in the 1950s that Key lime pie was promoted as Florida's "most famous treat" and in 1987 as "the greatest of all regional American desserts."