This easy Key lime pie recipe only calls for 3 ingredients for the filling and can be made as an unbaked or baked pie.

Overhead view of a classic key lime pie that is decorated with piped whipped cream and lime wedges

OVERVIEW

This beautifully bright and tart pie could not be easier to make. The recipe only calls for 3 ingredients in the filling and 3 ingredients in the crust.

A true Key lime pie is made with limes from the Florida Keys. The original recipe dates back to the 1930s and is now the official pie of Florida! Because it can be hard to find Key limes, it’s common to swap them out for regular limes. Either way, you will have a deliciously tart and sweet dessert that is simple to make.

What makes this recipe so easy

  • The number of ingredients is minimal. 3 ingredients for the crust and 3 ingredients for the filling. That’s it!
  • It takes less than half an hour to prepare the pie. The most difficult part of making it is the patience needed to chill it before eating.
  • Even if you can’t find true Key limes, don’t sweat it. This recipe also works well with regular limes.

Ingredients in Key Lime Pie

There are 3 essential ingredients in a Key lime pie filling.

Bowl of limes and someone holding a key lime on the left and a persian lime on the right with text over the image indicated which is which

Key Lime Juice: Typical limes that you find in the grocery store are called Persian limes. They are larger and more tart than Key limes. Key limes are smaller and have a brighter lime flavor. They are more commonly found between June and September. To the chagrin of Key lime pie purists, if you can’t find Key limes, you can swap them for Persian limes.

Stay away from bottled lime juice. Fresh is always better!

Sweetened Condensed Milk: This ingredient adds sweetness to the filling while balancing out the tartness of the limes. Canned milk was used in the original Key lime pie recipe because fresh milk and refrigeration were not yet common in the Florida Keys back in the 1930s.

Note: Make sure that you purchase sweetened condensed milk and not evaporated milk as the cans look very similar. If you do not have access to it, you can make homemade sweetened condensed milk with only milk and sugar.

Egg Yolks: The egg yolks in the recipe add richness to the filling and is the essential ingredient to set the filling and make it slice-able. Use the leftover egg whites to make a meringue topping.

Key Lime Zest: This ingredient is optional but gives the filling an extra boost of lime flavor. You can use the zest from a Key lime or Persian lime. To keep the filling perfectly smooth, leave it out.

Slice of key lime pie on a white plate with a fork

How to Make Easy Key Lime Pie

The only difficult part about making this pie is juicing the limes and waiting for it to solidify. Everything else comes together in a snap! This is a great pie to make with kids.

The Crust

Graham cracker pie crust baked in a pie plate

There is some disagreement about what type of crust should be used in a key lime pie: graham cracker crust or shortcrust? Either option would be delicious but I prefer the flavor and crunch of a thick graham cracker crust.

Although optional, I like to bake the crust for a short time before adding the filling. Not only does it give the crust a toasted flavor but also helps it to stay together when slicing.

The Filling

After adding the filling to the crust, you have the option of baking it or leaving it unbaked. Because lime juice is so acidic, it works to break down the proteins in the egg yolks which helps it to gel and set. I have made this pie as an unbaked version several times. However, I find that baking it for a very short period of time helps to set the filling more firmly, which I prefer.

The Topping

Whipped cream in a bowl

There is some debate on what makes a better topping for Key lime pie: meringue, whipped cream, or nothing at all. Although you can’t go wrong with a toasted meringue topping, I prefer just a tiny bit of lightly sweetened whipped cream to balance the tartness.

Chilling the Pie

It’s important to make sure the pie is completely chilled before slicing it, otherwise it will not set. I actually really love to slice the pie once it is set and keep some pieces in the freezer to eat frozen. The pie doesn’t get completely rock solid in the freezer and it is such a lovely cold treat!

Overhead view of a classic key lime pie that is decorated with piped whipped cream and lime wedges

MAKE-AHEAD EASY KEY LIME PIE

Make and bake the graham cracker crust and store in the refrigerator for up to 3 days and in the freezer up to 3 months. Do not make the filling in advance.

How to store in the refrigerator: A key lime pie can be stored in the refrigerator for 3-4 days. Wrap the pie in plastic wrap and don’t add whipped cream until serving.

How to store in the freezer: After the pie has fully cooled, wrap tightly in plastic wrap and freeze for up to 3 months. Enjoy frozen slices as a cold treat or thaw in the refrigerator for an hour or two.

MORE RECIPES FROM BAKER BETTIE!

If you enjoyed this recipe, you might like to try these other delicious pie recipes.

Overhead view of a classic key lime pie that is decorated with piped whipped cream and lime wedges
Yield: 8-10 servings

Easy Key Lime Pie with Graham Cracker Crust

Prep Time 30 minutes
Cook Time 24 minutes
Chilling Time 7 hours
Total Time 7 hours 54 minutes

This easy Key lime pie recipe only calls for 3 ingredients for the filling and 3 ingredients for the graham cracker crust! The pie can be baked or left unbaked.

Ingredients

For the Crust

  • 200 grams (7 ounces, about 2 cups once made into crumbs) graham crackers
  • 50 grams (¼ cup) granulated sugar
  • 113 grams (1 stick, ½ cup) unsalted butter, melted

For the filling

  • 227 grams (1 cup, 240 milliliters) Key lime juice
  • 1 teaspoon lime zest (optional)
  • 788 grams (2-14 oz cans) sweetened condensed milk
  • 5 large egg yolks

Instructions

MAKE THE CRUST

  1. Preheat the oven to 375°F/190°C.
  2. Place the graham crackers (200 grams, 7 ounces) into a food processor and pulse until you have very fine cookie crumbs. Alternatively, you can place them in a ziplock bag and use a rolling pin to roll back and forth over the cookies until they are fine crumbs. You do not want any large pieces. Pour the crumbs into a medium bowl. You should have about 2 cups.
  3. Stir in the granulated sugar (50 grams, ¼ cup) and the melted butte(113 grams, ½ cup) until all of the crumbs are completely coated with butter.
  4. Firmly press the crumb mixture into the bottom and up the sides of a 9 inch (23 cm) pie plate (not a deep dish pie plate). The bottom of a glass or a measuring cup can be helpful to press the crumbs into an even layer. Press down very firmly. Any gaps or loose crumbs will cause the filling to soak through and become soggy.
  5. Bake for 10-12 minutes. Allow to cool while making the filling.

Make the Filling

  1. After the crust is done baking, reduce the oven temperature to 350°F/175°C.
  2. Juice and zest (if using) the limes.
  3. Combine the lime juice (227 grams/ 1 cup), lime zest (1 teaspoon) if using, sweetened condensed milk (788 grams), and egg yolks (5 large) in a bowl and whisk until combined.
  4. Pour the filling into the pie crust (it doesn't have to be completely cooled) and bake for 12-14 minutes, until the filling is thickened but still slightly jiggly in the center.
  5. Allow the pie to cool at room temperature for 1 hour and then refrigerate for a minimum of 6 hours before slicing.
  6. Garnish with whipped cream, lime zest, and lime slices if desired.

Notes

Traditionally, the filling for a Key lime pie remains unbaked. If you would like to leave it unbaked you can. The acidity from the lime juice will help the egg yolks to gel and allow the filling to set. However, it will not set quite as firmly as it does when you bake it for a short period of time.

Recipe adapted from The Yearling Restaurant Key Lime Pie Recipe

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Nutrition Information:


Amount Per Serving: Calories: 0