How to Make Key Lime Pie — The Authentic Florida Keys Recipe

Transcript

Show Host: It is one forty-seven in the afternoon on Duval Street in Key West, the thermometer reads ninety-three degrees, and somewhere a screen door is slamming because a cold Key Lime Pie just came out of an icebox. That snap of pale-yellow citrus custard hitting your tongue is two-hundred-fifty years of Florida Keys history in one bite. Tonight we make a perfect one from scratch — graham crust, condensed-milk filling, fresh Key lime juice and zest, exact times and temperatures, and the Conch tradition behind every step. Joining me are a Pastry Chef out of Key West and an Upper Keys Citrus Grower.

Pastry Chef: Key Lime Pie was born in Key West around eighteen-fifty-six, right after Gail Borden patented sweetened condensed milk. Before that there was no fresh dairy on the island — no cattle, no ice. The Conch sponge fishermen and their families used the canned milk plus the natural acid of the local Key lime to chemically set the custard with no oven needed in the original version. Florida named it the official state pie in twenty-oh-six. Five real ingredients in the filling. Four egg yolks. One fourteen-ounce can sweetened condensed milk. Half a cup fresh Key lime juice. One tablespoon Key lime zest. Tiny pinch of salt.

Citrus Grower: Now the lime matters more than anything. A true Key lime is small — about the size of a ping-pong ball, an ounce or less of fruit. The flesh is pale yellow, not green. The juice is more aromatic, more floral, and a touch more bitter than a Persian lime. You will need about twenty to twenty-five Key limes to get one half cup of juice. If you must use Persian limes from the grocery, use twelve to fifteen and add a half teaspoon of fresh lemon juice to mimic the brightness. Never use bottled green plastic-bottle juice — it is preserved Persian juice and it tastes like dish soap. Zest before you juice.

Pastry Chef: Now the graham crust. Preheat the oven to three-hundred-fifty degrees Fahrenheit, that is one-hundred-seventy-five Celsius. In a bowl combine one and a half cups graham cracker crumbs — about fourteen full graham crackers pulsed in a food processor — with one third cup granulated sugar and six tablespoons of melted unsalted butter, which is three quarters of a stick. Mix it directly with your fingers until it looks like wet beach sand. Press it firmly and evenly up the sides and bottom of a nine-inch pie plate. Use the flat bottom of a measuring cup to pack it. Bake eight to ten minutes. Cool ten minutes before filling.

Citrus Grower: Now the filling, and please do not skip the zest, that is where the perfume lives. In a stainless mixing bowl whisk four large room-temperature egg yolks for two full minutes by hand until they go a touch paler and thicken slightly. Add the full fourteen-ounce can of sweetened condensed milk and one tablespoon of Key lime zest and whisk thirty seconds. Then slowly pour in one half cup of fresh Key lime juice while whisking, and whisk one more minute. The chemical reaction between the acid and the milk proteins is what sets the custard. Pour into the warm prebaked crust right away.

Pastry Chef: Bake the filled pie at the same three-hundred-fifty degrees Fahrenheit, one-hundred-seventy-five Celsius, on the middle rack, for exactly fifteen to seventeen minutes. The center should still wobble like a firm Jello when you nudge the pan — about a four-inch jiggle circle. The edges should be just set and slightly puffed. Pull it out, cool one hour on the counter, then refrigerate at least three hours, ideally overnight uncovered for the first hour then loosely covered. The chill is not optional — it is the second half of the set. Slice with a hot wet knife wiped between every cut.

Citrus Grower: Topping. Two paths and the Keys are split exactly down the middle. Whipped cream — one cup cold heavy cream, two tablespoons powdered sugar, half teaspoon vanilla, whipped to medium-stiff peaks, dolloped on each slice cold. Or torched meringue — four egg whites, half cup granulated sugar, quarter teaspoon cream of tartar, whipped to stiff glossy peaks, swirled over the chilled pie, then bruleed with a kitchen torch for about thirty seconds until the peaks are dark golden brown. Traditional is meringue. Modern Key West tourist counters lean cream. Both are correct.

Pastry Chef: Five common mistakes to avoid. One — green food coloring. A real Key Lime Pie is pale yellow. Green means somebody is hiding bottled juice. Two — overbaking past eighteen minutes. The filling goes from silk to chalk in two minutes flat. Three — cold ingredients. Bring the yolks and the condensed milk to room temperature first. Four — under-zesting. The zest carries seventy percent of the flavor. Five — slicing it warm. Refrigerate three hours minimum or it slumps. Serve cold, straight from the fridge, with a fresh lime wheel on top and a sweating glass of unsweetened iced tea on the side.

Show Host: Three takeaways. One — get real Key limes, twenty to twenty-five of them for one half cup of juice, and zest one tablespoon worth before you juice them. Two — bake the graham crust at three-fifty for eight to ten minutes, fill with four yolks plus a fourteen-ounce condensed milk can plus the half cup juice plus the zest, bake fifteen to seventeen minutes until the center wobbles in a four-inch circle, cool one hour and chill three. Three — pick your team, whipped cream or torched meringue, but skip the green food coloring forever. Thank you, Pastry Chef. Thank you, Citrus Grower.