My favorite fact about Key lime pie is that the man who claims to know the original version of the recipe found the recipe while researching a ghost. It may have been the ghost of the first baker of the pie, or else it was a ghost who lived somewhere else in a palatial mansion funded at least in part by the sale of one key Key lime pie ingredient.
My other favorite fact is that this man, David Sloan, a.k.a. the self-described leading American Key lime pie expert, is not a true Floridian, but a Texan adopted by the Southernmost part of the United States. He came to the Keys by way of college and cruise ships, but seemed to really come into his own once he got into the ghost tour business. It was during one of his tours of the home of William "Bill Money" Curry, who was a hardware magnate and the first person to bring sweetened condensed milk to the Keys in the mid-19th century, that Sloan found the recipe in a kitchen cupboard.
There are a few competing histories of Key lime pie. The first, and in my opinion, the most realistic, is that the first such "pies" were crustless and made from a mixture of lime juice, pelican eggs and sweetened condensed milk. These were assembled by sponge fishermen working in the ocean around the Keys, and were made without needing heat — the acid from the Key limes reacts with the egg yolks to thicken the mixture, almost like a custard, and the condensed milk acts as a sweetener. Another theory, albeit one usually discounted by historians, is that Key lime pie was an invention of botanist Jack Simons. The story Sloan believes is that the original pie came from that now-haunted mansion, and Curry's cook, known as "Aunt Sally." It was Aunt Sally's spirit, said Sloan, that led him to her original recipe, which he shared in his book, "The Ultimate Key Lime Pie Cookbook."