Traditional Key Lime Pie

by Haley // May 11, 2020 (updated May 26, 2023)

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The perfect blend of textures and flavors, this traditional key lime pie is uniquely sweet and tangy with a creamy consistency. The citrus custard filling is quick and easy to make from scratch while the homemade graham cracker crust adds a buttery crunch. You’ll love having this classic recipe on hand for your next gathering!

key lime pie whipped cream and lime wedges as garnish.

I’m just going to come out with it and say this key lime pie is simply the best. Seriously, you will love it. I’m not one for custard pies (I much prefer fudgy brownies), but this pie got me. The filling is the perfect balance of tangy and sweet while the graham cracker crust is buttery and thick.

My dad always begs me to make key lime pie for him because it’s his favorite. Now I understand why. When this pie is done right, it’s pure bliss. Let’s break it down, shall we?

Table of Contents

Why You’ll Love This Recipe

Traditional ingredients. This authentic recipe is made with key lime juice, egg yolks and sweetened condensed milk.
Perfect taste and texture. The tangy, sweet filling is like a custard—thick and creamy—and it sits on a buttery, yet sturdy, graham cracker crust.
Easy to make ahead of time. The pie can be made the day before and stored in the refrigerator right up until you’re ready to serve.
Delicious dessert for summer. This chilled dessert is refreshing on warm days. It’s light, citrusy flavors is a nice conclusion to a meal.
Eye-catching appearance. The bright yellow-green custard against the warm-colored crust makes a stunning contrast. It’s makes for an impressive dessert to serve guests!

Did You Know?

History has it that key lime pie originated in Key West, Florida, in the late 1800’s by a cook known as Aunt Sally. She cooked for a ship salvager and Florida’s first self-made millionaire William Curry.

Residents in the Keys relied on sweetened condensed milk because there was no delivery of fresh milk. The overseas highway to the Keys wasn’t built until 1930. The sweetened condensed milk and key limes are staple ingredients for the pie.

Ingredients

Key lime juice and zest: Use fresh lime juice and zest for the best taste.
Sweetened condensed milk: You will need one 14 ounce can for this recipe. It’s usually found in the baking aisle at your local grocery store.
Egg yolks: I find that separating the eggs when they are cold is much easier. Let them come to room temperature before using in the recipe.
Graham crackers: You will need 10 graham cracker sheets (or 1 cup crumbs) to make the crust.
Heavy cream: If you choose to make the whipped cream topping from scratch, make sure the heavy cream is cold.
Confectioners’ sugar: For a little sweetness in the whipped cream, add 1 tablespoon sugar.

Refer to the recipe card for exact measurements and detailed ingredient information.

Recipe Variations

Add coconut to the graham cracker crust. I do this in my coconut cream pie recipe and it tastes delicious! Use 9 graham cracker sheets instead of 10 and add 1/4 cup toasted coconut to the food processor. Blend crackers and coconut until fine crumbs form.

Try a different size. Use tartlet pans to make mini pies (yields 5 to 6). You can also use this recipe to make key lime pie bars in an 8×8-inch baking pan.

Make a different crust. Try using Nilla wafers or chocolate graham crackers to make the crust! Aim for about 1 cup fine crumbs.

Add some garnish. I prefer a simple whipped cream and lime slices, but you can also garnish the pie with strawberries, chocolate shavings or make a meringue topping.

How to Make Traditional Key Lime Pie

photo collage demonstrating how to make graham cracker crust and key lime pie filling in a mixing bowl.

Make the graham cracker crust: In a food processor, pulse graham crackers until find crumbs form. Add sugar and melted butter, and process until combined.
Bake crust: Transfer graham cracker mixture to a 9-inch springform pan. Press it firmly into the bottom and 1 inch up the sides of the pan. Bake at 325 F for 15 minutes.
Make the key lime filling: Whisk egg yolks and lime zest together until it turns a greenish-yellow.
Add sweetened condensed milk and lime juice. Whisk thoroughly, then let the mixture sit for 30 minutes to thicken.

photo collage showing key lime pie before and after being baking, chilled and decorated.

Bake the pie: Transfer the filling to the cooled graham cracker crust. Bake at 325 F for 15 to 17 minutes. Cool to room temperature, then chill the pie in the refrigerator for 3 hours.
Garnish: Make the whipped cream toppings by whisking together the heavy cream, confectioners’ sugar and vanilla until stiff peaks form. Decorate the pie with fresh whipped cream and lime slices.

Expert Tips

Use fresh key lime juice and zest. This is where the unique flavors comes from! Zest and juice the limes yourself. In a pinch, regular limes work or you can use Nellie and Joe’s key lime juice, but you will still need fresh lime zest.

Make the crust from scratch. It tastes much better than store-bought crust—believe me! It’s worth the extra effort.

Don’t over-bake. You know the pie is done when it’s creamy and jiggle slightly in the center when gently shaken. If the pie is over-baked, it will crack and become dry.

Let the pie cool completely and then chill it for 3 hours before serving. This is essential for any type of custard pie because it helps the curd filling set. Don’t put the pie in the refrigerator if it is still warm otherwise condensation will occur on top of the filling.

key lime pie slice on plate with two forks next to some limes.

Make Ahead and Storage Tips

Make ahead: The graham cracker crust may be made ahead and storage covered in the refrigerator for up to 3 days or frozen for up to 3 months. The filling cannot be made ahead of time as the acidity in the lime juice will cause the filling to separate.

Storage: After the pie has cooled completely, store it covered in the refrigerator for up to 3 days. I suggest garnishing right before serving for best results.

Freezing: Once the pie has cooled, place it as is in the freezer to set and harden (about 2 hours). Remove pie from the freezer and detach the side of the springform pan (leave the bottom or transfer to a cake board). Wrap the pie in plastic wrap, then aluminum foil to prevent freezer burn. Freeze the pie for up to 2 months. Defrost in the refrigerator before cutting and serving cold.

Frequently Asked Questions

What’s the difference between regular limes and key limes?

Key limes are packed with more acidity and flavor. They are found in Florida and are smaller than standard Persian limes you typically buy at the grocery store.

Can you use regular limes in key lime pie?

Technically yes, you can use regular limes in key lime pie. I have made this recipe with both key limes and Persian limes, and there was only a subtle difference in taste. Key limes added a touch more flavor.

Can I use bottled lime juice?

If you can’t find key limes, the solution is to use Nellie & Joe’s Key Lime Pie Juice—I swear by this stuff. Do not use regular store bought lime juice. It doesn’t provide nearly enough flavor.