Key lime pie [kee lahym pahy] noun
A pie typically featuring graham cracker crust and a filling made with Key lime juice, sweetened condensed milk and egg yolks. Many variations exist, and Key lime pie is a staple throughout the Florida Keys and popular throughout the U.S.
The exact origin of the pie is unknown, but it does date back to the late 19th century, when it was probably prepared with a pastry crust (sometimes seen today as well). Key limes are native to the Florida Keys and are considered more fragrant than the supermarket Persian lime. Their juice is yellow, so do not expect your pie filling to be green. When the condensed milk and the acidic lime juice are combined, a reaction occurs that thickens the mixture, which is only further enhanced by the egg yolks.
In traditional key lime pie recipes, the directions are for uncooked filling, but since consumption of raw eggs can be problematic for some, many recipes now recommend baking the pie for a brief stint in the oven. Baking also thickens the texture, resulting in a more reliably set-up filling. Sometimes topped with meringue (which uses the leftover egg whites), other times with whipped cream, this pie is a great combination of sweet and tart flavors.