Coastal Key Lime Pie with a Crisp Graham Crust

Coastal Key lime pie is a Florida favorite made with tart Key lime juice, sweetened condensed milk, egg yolks, and a crisp graham cracker crust. This version balances bright citrus with a smooth, gently set filling and a cloud of whipped cream; bottled Key lime juice works when fresh Key limes are hard to find.

Ingredients

1 ½ cups (150 g) finely crushed graham cracker crumbs
⅓ cup (67 g) granulated sugar
6 tablespoons (85 g) unsalted butter, melted
1 tablespoon finely grated Key lime zest, plus a little extra for garnish (about 6–8 Key limes)
¾ cup (180 ml) Key lime juice, freshly squeezed or bottled
4 large egg yolks
2 cans sweetened condensed milk, 14 ounces (396 g) each
1 cup (240 ml) cold heavy cream
2 tablespoons (15 g) confectioners’ sugar
½ teaspoon vanilla extract

Instructions

Prepare the oven and pan. Heat the oven to 350°F (175°C). Set a 9-inch (23 cm) pie plate on a rimmed baking sheet, which makes it easier to move in and out of the oven.
Make the crust. Stir the graham cracker crumbs and granulated sugar together in a bowl. Pour in the melted butter and mix until the crumbs are evenly damp and hold together when pressed. Tip them into the pie plate and press firmly across the bottom and up the sides, using the flat bottom of a measuring cup to compact the crust. Bake for 8 minutes, then set it aside to cool slightly while you mix the filling.
Mix the filling. In a large bowl, whisk the egg yolks and lime zest for about 1 minute, until slightly thickened. Whisk in the condensed milk, then the lime juice, until smooth. Pour the mixture into the warm crust and spread it evenly. Avoid prolonged whisking once the juice is added; a few bubbles are harmless, but excessive air can make the surface uneven.
Bake until just set. Bake for 15–17 minutes. The outer edge should look set, while the center should still have a slight, cohesive wobble when the pie is gently nudged; it should not look liquid. Because the filling contains eggs, use a clean food thermometer to check the center: the USDA FSIS safe minimum for egg dishes is 160°F (71°C). If needed, return the pie to the oven in 2-minute increments until it reaches that temperature, taking care not to overbake it.
Cool and chill. Let the pie cool on a rack for about 1 hour, then cover loosely and refrigerate for at least 4 hours, or until fully cold and firm. Chilling is essential for clean slices; do not leave the pie at room temperature for more than 2 hours.
Whip the cream and serve. Just before serving, beat the cold heavy cream, confectioners’ sugar, and vanilla in a chilled bowl until medium peaks form. Spoon or pipe the cream over the pie and finish with a little lime zest. Slice with a thin knife wiped clean between cuts.

Tips

Choose the lime juice you like. Key limes are smaller, more aromatic, and often more tart than standard Persian limes. If fresh Key limes are unavailable, bottled Key lime juice is convenient and consistent; ordinary fresh lime juice is a practical substitute, though its flavor is usually less floral. Keep the total juice at ¾ cup (180 ml).
Press the crust firmly. Loose crumbs can crumble when sliced. Compact the mixture evenly, especially where the bottom meets the sides, but do not make the sides unusually thick or they may bake unevenly.
Watch the center, not just the clock. Ovens and pie plates vary. The filling should be set around the edges and slightly wobbly in the middle before the thermometer check. Baking until completely rigid can produce a grainy or cracked filling.
Plan ahead and keep it cold. The pie needs at least 4 hours of chilling after its cooling hour, so it is a good make-ahead dessert. Add whipped cream close to serving time for its best texture.

Serving Suggestions

Serve the pie cold in modest wedges: its filling is rich, and the lime keeps each bite lively. A spoonful of whipped cream and a pinch of finely grated zest are classic, simple finishes. For a relaxed coastal-style dessert spread, pair it with fresh berries or sliced mango, or offer unsweetened iced tea or coffee alongside. Keep garnishes light so they do not hide the citrus flavor.

Variations

Use a different crumb crust: Replace the graham crackers with the same weight of finely crushed vanilla wafers or digestive biscuits. The crust will be a little sweeter or more buttery depending on the biscuits, so taste the crumb mixture before adding extra sugar.

Add a coconut note: Replace ¼ cup (25 g) of the graham crumbs with finely shredded unsweetened coconut. Press and bake the crust as directed; the toasted coconut gives it a gentle tropical flavor without changing the filling.

Serve it without whipped cream: The pie is flavorful on its own. For a sharper finish, garnish with extra zest instead of sweetened cream. Avoid adding extra juice to the filling, since changing the liquid balance can keep it from setting as intended.

Storage and Reheating

Refrigerate the pie, covered, within 2 hours of baking or serving. It keeps well for 3–4 days in the refrigerator; store whipped cream separately if possible and top each slice when serving. Do not leave it out for extended periods, especially in warm weather. The pie is served chilled, so reheating is not recommended. For longer storage, freeze the cooled pie without whipped cream, tightly wrapped, for up to 1 month. Thaw it overnight in the refrigerator and add fresh whipped cream after thawing; the crust may soften slightly.

Frequently Asked Questions

Can I use regular lime juice instead of Key lime juice?
Yes. Use ¾ cup (180 ml) fresh juice from standard Persian limes. The result will still be tart and delicious, though it will lack some of the distinctive floral aroma of Key limes. Do not increase the amount to compensate.

Can I use bottled Key lime juice?
Yes. Bottled Key lime juice is a useful option when fresh fruit is unavailable. Use the same measured amount, ¾ cup (180 ml), and check that the bottle contains lime juice rather than a sweetened drink or lime cordial.

Why is my pie runny?
It may have needed more oven time, a full chill, or both. Check that the center reached 160°F (71°C), then allow the pie to cool and refrigerate it for at least 4 hours. Slicing while it is warm or only partly chilled can also make a properly baked pie seem loose.

Can I make Key lime pie a day ahead?
Yes. Bake and chill it, then cover it once cold and refrigerate overnight. For the neatest presentation, add the whipped cream shortly before serving rather than storing the pie with the topping already on it.

Does Key lime pie need to be refrigerated?
Yes. Its egg-and-dairy filling should be refrigerated, and the pie should not sit at room temperature for more than 2 hours. Return leftovers to the refrigerator promptly.

How do I get clean slices?
Chill the pie until fully firm, then use a thin, sharp knife. Dip the blade in warm water and wipe it dry between cuts. This helps the knife pass through the filling and crust without dragging crumbs across the surface.

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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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