Key lime pie is an American dessert made of Key lime juice, egg yolks, and sweetened condensed milk in a pie crust. The traditional Conch version uses the egg whites to make a meringue topping.
The dish is named after the small Key limes (Citrus aurantifolia ‘Swingle’) that are naturalized throughout the Florida Keys. While their thorns make them less tractable, and their thin, yellow rinds more perishable, Key limes are more tart and aromatic than the common Persian limes seen year round in most U.S. grocery stores.
Key lime juice, unlike regular lime juice, is a pale yellow. The filling in Key lime pie is also yellow, largely due to the egg yolks.
During mixing, a reaction between the condensed milk and the acidic lime juice occurs which causes the filling to thicken on its own without requiring baking. Many early recipes for Key lime pie did not require the cook to bake the pie, relying on this chemical reaction (called thickening) to produce the proper consistency of the filling. Today, in the interest of safety due to consumption of raw eggs, pies of this nature are usually baked for a short time. The baking also thickens the texture more than the reaction alone.
Key Lime Pie
adapted from Martha Stewart’s Pie’s & Tart’s
- 6-1/2 pint mason jars
- 1 can (14 ounces) can sweetened condensed milk
- 4 large eggs separated
- 3/4 cup freshly squeezed key-lime juice (about 20 key limes)
- Graham Cracker Crust (see recipe below)
- 1/2 cup plus 1 Tablespoon granulated sugar
- 1 1/2 cups graham-cracker crumbs (12 graham crackers – pulverized in the food processor)
- 6 tablespoons unsalted butter, melted and cooled
- 3 tablespoons sugar
- Pinch of salt
- Heat oven to 375 degrees. Butter or grease mason jars and arrange them in an 11×7 baking dish. *This makes moving them in & out of the oven much easier!
- Combine graham-cracker crumbs, melted butter, and 3 tablespoons sugar in a medium bowl; mix well. Divide evenly among the prepared jars and press flat into the bottom. Bake until lightly browned, about 12 minutes. Remove from oven, and transfer to a wire rack until completely cooled. *Be careful, jars will be very hot!
- Lower oven to 325 degrees. In a medium bowl, gently whisk together condensed milk, egg yolks and Key lime juice. Pour into the cooled jars.
- Return pies to oven, and bake until the center is set but still quivers when the pan is nudged, 15 to 17 minutes. Let cool completely on a wire rack.
- Beat granulated sugar and egg whites in the bowl of an electric mixer. Place bowl over (not in) a pan of simmering water, and stir until warm to the touch and sugar is dissolved. (this is quick) Attach the bowl to the stand of the mixer and beat on medium high until stiff peaks form and meringue is glossy, about 5 minutes.
- Spoon meringue onto cooled pies. *At this point you can finish the pies with a garnish of lime zest or stick them back in the oven for about 5 minutes until golden brown on top. Serve pies immediately once at room temperature.