This key lime pie has a buttery graham cracker crust, a custardy filling made with fresh key lime juice and sweetened condensed milk, and a total bake time of just 20 minutes. The filling sets firm enough to slice cleanly, which makes it a reliable choice when you need a dessert that travels well or feeds a group without any last-minute fuss. Four ingredients in the filling, nothing exotic, and the whole thing can be made the day before.
Why this recipe works
Two things make this pie work. First, beating the egg yolks before adding the condensed milk gives the filling a slightly lighter texture and helps it set evenly — skip that step and you risk a dense, rubbery center. Second, baking the crust before adding the filling keeps it from going soggy once the wet filling goes in. Ten minutes at 350°F is enough to bind the crumbs so the crust holds a clean slice even after several hours in the fridge. The short second bake — just 10 minutes for the filling — is enough to set it without overcooking, which would dull the bright lime flavor.
Shopping notes
- Key limes: They’re smaller than Persian limes and noticeably more tart and floral. You’ll need roughly 12–15 key limes to get a half cup of juice. If your store doesn’t carry them, Nellie & Joe’s bottled key lime juice is a widely available and acceptable substitute — just don’t use regular lime juice, which tastes flat by comparison.
- Sweetened condensed milk: One standard 14-oz can is exactly what this recipe calls for. Do not substitute evaporated milk — it’s unsweetened and the filling won’t set correctly.
- Graham cracker crumbs: Pre-crushed crumbs from a box work fine, but crushing whole crackers in a zip-lock bag gives a slightly coarser texture that holds together better in the crust.
Keeping and reheating
Cover the pie loosely with plastic wrap and refrigerate for up to 4 days — the flavor actually improves on day two as the lime mellows into the filling. For longer storage, freeze the whole pie or individual slices wrapped tightly in plastic and then foil for up to 1 month. Thaw overnight in the fridge, not on the counter. This pie is served cold, so there’s no reheating involved; just pull it out of the fridge about 10 minutes before slicing to make cutting easier. Skip the garnish — not worth the extra dish — the pie is good enough on its own.
If something goes sideways
- Filling is still jiggly after baking: A slight wobble in the very center is fine — it firms up during chilling. If the whole surface moves like liquid, bake in 2-minute increments until only the center jiggles. Do not rely on color alone; the filling stays pale yellow throughout.
- Crust crumbles when you slice: The butter ratio is the usual culprit. Make sure all the crumbs are evenly coated before pressing — dry patches won’t bind. Also press firmly and evenly up the sides; loose packing is the main reason slices fall apart.
- Filling tastes flat or not tart enough: This almost always means the key lime juice was bottled Persian lime juice rather than actual key lime juice. The flavor difference is significant. If you’re mid-recipe and realize this, stir in an extra teaspoon of lime zest to boost the citrus punch.
- Crust shrinks down the sides during baking: The mixture wasn’t pressed firmly enough before it went into the oven. Next time, use the flat bottom of a measuring cup to compress the sides. For now, the pie is still fine — you’ll just have shallower edges.
- Filling weeps or looks watery after chilling: This usually means the pie wasn’t chilled long enough before slicing. Three hours is the minimum; overnight is better, especially if you’re serving a crowd and cutting multiple slices at once.
Easy Key Lime Pie with Graham Cracker Crust
Equipment
- 9-inch (23cm) pie dish
- Mixing bowl (large)
- Mixing bowl (medium)
- Citrus juicer or reamer
- Microplane or fine grater (for zesting)
- Offset spatula or back of a spoon
Ingredients
Crust
- 1 ½ cups graham cracker crumbs 150g; preferably crushed from whole graham crackers for best texture
- ⅓ cup granulated sugar 65g
- 6 tablespoons unsalted butter melted, 85g
Filling
- 4 large egg yolks at room temperature
- 14 ounces sweetened condensed milk 396g / one 14-oz can
- ½ cup key lime juice freshly squeezed, 120ml — approximately 20-25 key limes
- 1 tablespoon lime zest
Instructions
- Preheat the oven to 350°F / 180°C (160°C fan-forced). In a mixing bowl, combine the graham cracker crumbs, sugar, and melted butter until the mixture resembles wet sand.1 1/2 cups graham cracker crumbs, 1/3 cup granulated sugar, 6 tablespoons unsalted butter
- Press the mixture firmly into a 9-inch (23 cm) pie dish to form an even crust, making sure to press up the sides as well. Bake the crust for 10 minutes, then set aside to cool.1 1/2 cups graham cracker crumbs, 1/3 cup granulated sugar, 6 tablespoons unsalted butter
- In a large mixing bowl, beat the egg yolks until they lighten in color, then gradually mix in the sweetened condensed milk. Stir in the freshly squeezed key lime juice and lime zest until thoroughly combined.4 large egg yolks, 14 ounces sweetened condensed milk, 1/2 cup key lime juice, 1 tablespoon lime zest
- Pour the lime filling into the prepared crust, smoothing out the top with a spatula. Bake for 10 minutes, just until the filling has set and looks glossy.4 large egg yolks, 14 ounces sweetened condensed milk, 1/2 cup key lime juice, 1 tablespoon lime zest
- Allow the pie to cool at room temperature for 30 minutes, then cover loosely with plastic wrap and refrigerate for at least 3 hours or until fully chilled before serving.
Notes
Nutrition
FAQ
Can I make this pie the day before serving?
Yes, and it’s actually better that way. The filling firms up fully overnight and the lime flavor settles into the crust. Just cover it loosely with plastic wrap and keep it refrigerated until you’re ready to serve.
Can I double the recipe to make two pies?
Yes, this recipe doubles cleanly. Mix the crust and filling in larger bowls and prepare two 9-inch pie dishes side by side. Both can bake at the same time on the same oven rack — just rotate them halfway through the filling bake to account for any hot spots.
What’s the difference between key limes and regular limes?
Key limes are smaller, seedier, and more acidic than the Persian limes you typically find at the grocery store. They also have a slightly floral, almost herbal note that regular limes don’t have, which is what gives the pie its distinctive flavor.
Do I really need to use fresh key lime juice, or is bottled okay?
Bottled key lime juice (specifically labeled key lime, not regular lime juice) works well here. Freshly squeezed is slightly brighter, but the difference is small enough that bottled is a practical choice, especially when you need a lot of juice for multiple pies.
How do I know when the filling is done baking?
The edges should look set and the surface should appear glossy, with only a small wobble in the very center when you gently shake the dish. It will continue to firm up as it cools and chills, so don’t overbake trying to eliminate all movement.
Can I make this without egg yolks?
The egg yolks are what sets the filling into a sliceable custard, so leaving them out entirely won’t work. If you need an egg-free version, a small amount of cornstarch mixed into the filling can help it set, though the texture will be slightly different — more pudding-like than custardy.
More recipes to try
- Zesty French Lemon Cake
- Sunshine in a Jar: Classic British Lemon Curd
- Elegant Pavlova with Fresh Berries
- Heavenly Strawberry Cake with Fresh Berries and Whipped Cream
