Alison Roman Key Lime Pie with a Salty Crust

Alison Roman’s key lime pie is a tart, creamy citrus pie with a crisp graham cracker crust and a softly whipped cream topping. This version follows the appealing sweet-salty balance associated with her approach, using fresh lime juice and a simple baked filling; regular Persian limes work well if key limes are hard to find.

Ingredients

2 cups (200 g) finely crushed graham cracker crumbs, about 14 full cracker sheets
5 tablespoons (70 g) unsalted butter, melted
2 tablespoons (25 g) granulated sugar
½ teaspoon (3 g) fine salt, divided
4 large egg yolks, preferably at room temperature
1 can (14 ounces / 397 g) sweetened condensed milk
½ cup (120 ml) fresh key lime juice or Persian lime juice, from about 12–16 key limes or 3–4 Persian limes
1 tablespoon finely grated lime zest, from about 2 limes
1 cup (240 ml) cold heavy cream
1 tablespoon (8 g) confectioners’ sugar
¼ teaspoon vanilla extract
Flaky salt, for finishing, optional

Instructions

Heat the oven to 350°F (175°C). Set a rack in the center. Lightly butter a 9-inch (23 cm) pie plate, or leave it ungreased if it has a nonstick finish.
Combine the graham cracker crumbs, melted butter, granulated sugar and ¼ teaspoon of the fine salt in a bowl. Stir until the crumbs are evenly moistened and resemble damp sand. Press the mixture firmly over the bottom and up the sides of the pie plate, using the bottom of a measuring cup to compact it. Bake for 8 minutes, then set the crust aside while you prepare the filling.
In a medium bowl, whisk the egg yolks until smooth. Whisk in the sweetened condensed milk, lime juice, lime zest and remaining ¼ teaspoon fine salt until thoroughly combined. The mixture will thicken slightly as the citrus reacts with the condensed milk. Pour it into the warm crust and smooth the top.
Bake for 12 minutes, until the edges look set and the center still has a slight, even wobble when the pie plate is nudged. The filling should not be browned or bubbling vigorously. The USDA FSIS safe minimum temperature for egg dishes is 160°F (71°C); check the center with a food thermometer if you need to verify doneness. Remove the pie from the oven and cool at room temperature for 1 hour.
Cover the cooled pie without touching its surface and refrigerate for at least 4 hours, or until fully chilled and firm. Do not skip this setting time: cutting too soon can leave the filling loose.
Just before serving, whip the cold heavy cream, confectioners’ sugar and vanilla in a chilled bowl until it holds soft peaks. Spoon or spread the cream over the pie. Finish with a little flaky salt if desired, then cut into slices with a clean, sharp knife.

Tips

Choose your limes: Key limes are small, aromatic and often sharper than Persian limes. Persian limes are a reliable substitute and make the pie slightly less floral. Use freshly squeezed juice rather than bottled juice for a brighter flavor.
Press the crust firmly: Compact crumbs make a sturdier base that is less likely to crumble when sliced. If your graham crackers are already sweetened, the small amount of added sugar still works, but you can reduce it to 1 tablespoon (12 g).
Watch the center, not just the clock: Ovens and pie plates vary. A gentle wobble is expected; a liquid center needs more time, while a fully firm or browned filling may be overbaked and less silky.
Keep the topping cold: Whip the cream just before serving for the best texture. For cleaner slices, chill the pie thoroughly and wipe the knife between cuts.

Serving Suggestions

Serve the pie cold, in modest wedges: its sweet, rich filling and sharp citrus flavor make it satisfying without a large portion. A few extra flecks of lime zest or a pinch of flaky salt bring out the contrast between tartness and sweetness. It pairs well with plain coffee or unsweetened iced tea. Add the whipped cream at the table if the pie will sit out for a while, so the topping stays airy.

Variations

For a more pronounced lime flavor, add another teaspoon of finely grated zest, but avoid grating the bitter white pith. A pinch of ground ginger in the crust adds gentle warmth; start with ¼ teaspoon (about 0.5 g). You can also replace up to ½ cup (50 g) of the graham crumbs with finely crushed digestive biscuits, which give the base a slightly more buttery, less honeyed taste. For a simpler finish, omit the whipped cream and serve each slice plain. These are flexible adaptations rather than required parts of the pie.

Storage and Reheating

Refrigerate the pie within 2 hours of baking or serving. Cover it and keep it refrigerated at 40°F (4°C) or colder for up to 3 days; for best texture, add the whipped cream shortly before serving. If already topped, store it covered and expect the cream to soften somewhat. Do not leave the pie at room temperature for more than 2 hours, or more than 1 hour if the room is above 90°F (32°C). This pie is served cold and should not be reheated. Freezing is possible, but the filling and cream can become less smooth; freeze the pie without topping, tightly wrapped, for up to 1 month, then thaw overnight in the refrigerator and add fresh cream.

Frequently Asked Questions

Can I use regular limes instead of key limes?
Yes. Persian limes are widely available and work in the same quantity. Their flavor is a little less fragrant and usually less sharp, but fresh juice and zest still give the pie a bright citrus taste.

Can I use bottled lime juice?
Fresh juice is preferable because it tastes brighter and more aromatic. Bottled juice can work in a pinch; use ½ cup (120 ml), and add fresh lime zest if available. Avoid sweetened lime cordial, which changes the filling’s sweetness and acidity.

Why is my filling runny?
It may have been underbaked, cut before chilling, or not refrigerated long enough. The center should have only a slight wobble after baking, and the pie needs at least 4 hours in the refrigerator to set. Keep it chilled until serving.

Can I make the pie ahead?
Yes. Bake and chill it a day ahead, keeping it covered in the refrigerator. Whip the cream and top the pie shortly before serving for the freshest texture.

Is the egg filling fully cooked?
The filling is baked, but visual cues alone do not confirm a specific internal temperature. USDA FSIS guidance sets 160°F (71°C) as the safe minimum for egg dishes; use a food thermometer in the center if you need to confirm it. Avoid tasting uncooked filling.

Can I make it without a pie plate?
A 9-inch (23 cm) tart pan can work, though a removable base may make delicate slices harder to lift. Press the crust evenly and handle the chilled pie carefully. A standard pie plate is the easiest option.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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