Equipment
* optional
Ingredients
Graham Cracker Crust
- 150 g graham cracker crumbs
- 30 g granulated sugar
- 1 g salt
- 75 g unsalted butter, melted
Key Lime Filling
- 4 egg yolks
- 6 g key lime zest
- 396 g sweetened condensed milk
- 120 ml key lime juice, freshly squeezed
Garnish
- 120 ml heavy whipping cream, chilled
- 15 g powdered sugar
- 1 key lime, sliced into wheels
Nutrition (per serving)
Nutrition is estimated per serving. Nutrients without complete source data are omitted.
Full nutrition
- Calories
- 405 kcal
- Protein
- 7 g
- Carbohydrates
- 50 g
- Fat
- 21 g
- Fiber
- 1 g
- Sugar
- 38 g
- Sodium
- 239 mg
- Saturated Fat
- 12 g
- Trans Fat
- 0 g
- Monounsaturated Fat
- 6 g
- Polyunsaturated Fat
- 2 g
- Cholesterol
- 151 mg
- Potassium
- 263 mg
- Calcium
- 248 mg
- Iron
- 1.0 mg
- Magnesium
- 26 mg
- Phosphorus
- 205 mg
- Zinc
- 0.9 mg
- Vitamin A
- 197 mcg
- Vitamin C
- 7 mg
- Vitamin D
- 0.8 mcg
- Vitamin E
- 0.9 mg
- Vitamin K
- 2 mcg
- Vitamin B6
- 0.1 mg
- Vitamin B12
- 0.4 mcg
- Thiamin
- 0.16 mg
- Riboflavin
- 0.33 mg
- Niacin
- 0.9 mg
- Folate
- 36 mcg
- Water
- 47 g
Sources: USDA FoodData Central
Method
Preheat the oven to 175°C (350°F).
In a mixing bowl, combine the graham cracker crumbs, granulated sugar, salt, and melted unsalted butter. Mix thoroughly until the texture resembles wet sand.
Transfer the crumb mixture to a 9-inch pie dish. Press firmly and evenly into the bottom and up the sides of the dish using a spatula or the bottom of a flat glass to form the crust.
Bake the crust at 175°C (350°F) for 10 minutes until lightly browned and fragrant. Remove from the oven and let it cool slightly on a wire rack.
In a clean mixing bowl, use a whisk to beat the egg yolks and key lime zest together for about 2 minutes, until the yolks become slightly pale and very fragrant.
Add the sweetened condensed milk to the yolk mixture and whisk continuously until fully incorporated and smooth.
Slowly pour the key lime juice into the bowl while whisking gently. The mixture will begin to thicken naturally as the acidic lime juice reacts with the dairy.
Pour the thickened lime filling into the pre-baked graham cracker crust, spreading it into an even layer with a spatula.
Bake the pie at 175°C (350°F) for 15 minutes. The edges should be set, but the center should still have a slight jiggle. Ensure the internal temperature of the filling reaches 74°C (165°F) so the yolks are fully cooked and safe to consume.
Remove the pie from the oven and let it cool completely on a wire rack to room temperature. Transfer to the refrigerator and chill for at least 4 hours to fully set the filling.
In a clean mixing bowl, whip the chilled heavy whipping cream and powdered sugar together using a whisk or hand mixer until medium peaks form.
Pipe or dollop the whipped cream around the border of the chilled pie and garnish with a fresh key lime wheel before serving.
Chef's Notes
- Bottled key lime juice can oxidize quickly and taste bitter. Always use freshly squeezed key limes, or a mixture of standard Persian limes and fresh lemon juice if key limes are unavailable.
- The reaction between the sweetened condensed milk and the acidic lime juice naturally thickens the filling, a chemical process called souring. The baking step is primarily to set the yolks and ensure food safety.
- For the neatest slices, wipe your knife blade with a warm, damp kitchen towel between each cut when serving the chilled pie.
Storage
Refrigerator: 4 days — Cover loosely with plastic wrap or a pie dome
Freezer: 1 month — Freeze solid before wrapping tightly in foil; thaw overnight in refrigerator before serving
Troubleshooting
Filling is runny and does not hold its shape when sliced
Cause: Pie was not chilled long enough, or too much liquid lime juice was added
Fix: Place the pie in the freezer for 1 to 2 hours to firm up the texture before serving
Prevention: Ensure the pie chills for a full 4 hours minimum before slicing and measure liquid ingredients precisely
Bitter flavor in the filling
Cause: Using bottled key lime juice which oxidized, or grating the bitter white pith of the lime
Fix: Cannot be fixed, but serving with extra sweetened whipped cream can help balance the bitterness
Prevention: Always use fresh key limes, and zest with a microplane using a light touch to only remove the green skin
Cultural Context
Key lime pie originated in Key West, Florida in the late 19th century, traditionally attributed to local sponge fishermen or a cook known as Aunt Sally. An authentic key lime pie is always pale yellow, never green, deriving its natural color from the egg yolks.
