By Kelly Blanco and Trevor Green

Indulging in a slice of refreshing key lime pie is a quintessential Florida experience.

 “Key lime pie is our number-one seller,” said Angie Wittke, who owns Mrs. Mac’s Kitchen in Key Largo. “People walk in and say, ‘We’re here for the pie.’”

The tart confection was named the official state pie in 2006, but its origins date to the 1860s. Commercially grown key limes were plentiful, and when the acidic lime juice was mixed with egg yolks and condensed milk, the filling would thicken without needing to be baked. The creamy filling was poured into a pastry crust and topped with a whipped meringue made from sugar and the leftover egg whites.

Variations of the Florida Key lime pie have emerged over the years, but one rule holds true: Key lime pie must be made with real key limes. In fact, in 1965, Florida state Rep. Bernie Papy Jr. introduced (ultimately unsuccessful) legislation calling for a $100 fine to be levied against anyone advertising Key lime pie that was not made with Key limes.

About the size of a golf ball, with a thin yellow rind, the Key lime is tart and aromatic with a bitter flavor. The juice is yellow (never green!) and it colors the filling of Key lime pie.

If you’re going to make Key lime pie at home, it can be a challenge to find the small fruit in the grocery store or at the farmers market. Most commercial crops were wiped out by citrus canker and the 1935 hurricane. But chef Justin Timineri, culinary ambassador for the Florida Department of Agriculture and Consumer Services, says it’s worth the hunt.

“It’s imperative to track down the fresh key limes," he said "There are some brands that do a good bottled juice, but to make the real-deal pie, you want to squeeze your own. It takes about 10 limes.”

In addition to the juice, there’s another key component.

“I like my pie nice and cold,” Timineri said. “I even put it in the freezer for 10 to 15 minutes to put an extra chill on it."