An American dessert classic, Key lime pie is the official state pie of Florida. If you’ve never had one, this sweet, tart, and creamy pie is sure to become a favorite after just one bite. Key lime pie can be made several ways, and this recipe utilizes a macadamia graham crust and plenty of whipped cream topping for an unforgettable yet easy dessert where everyone will ask for seconds.
I can’t remember exactly where I had key lime pie for the first time, but I think it was at a seafood restaurant in Myrtle Beach or Florida, and it quickly became one of my top 3 favorite pies ever. With a taste and texture somewhat between a lime curd and a cheesecake, it’s a lot different from other fruit pies like apple or cherry or blueberry. Citrus fruits make some great pies, but whole chunks in a pie just don’t quite have the same appeal as apple or pear pies do.
In 2006, the Florida legislature passed a statute naming Key lime pie the official Florida state pie. Both the fruit and the pie have an interesting history, and while the true origins of this pie have been lost to time, there’s plenty of controversy over who and where created Key lime pie.
The History of Key Lime Pie
How We Got Key Limes
Key limes are a citrus hybrid of the micrantha and citron fruits and originated in Malaysia and other areas of Southeast Asia. Eventually they made their way into the Middle East, then North Africa and parts of the Mediterranean where Spanish explorers brought them with them to the Caribbean islands and the Florida Keys. Also known as the West Indian lime and Mexican lime (and several other names), Key limes are smaller, with more seeds, a more floral note, and a much thinner rind than the standard Persian limes that are most common today. Their juice is also yellow, not green, so if you get a green Key lime pie, it was either dyed or not made with Key limes.
During the Great Freeze of 1894-95, Florida’s lemon groves were destroyed, and the farmers replanted with Mexican limes. Eventually these new crops became known as the Florida Key limes and the name stuck. Unfortunately, the Great Miami Hurricane of 1926 came in and destroyed the Key lime industry as well, and they got replaced with the more common Persian limes. While Florida and a few other areas in Texas and California do still grow Key limes, most of the commercially available Key limes on the market today are grown in Mexico, Central and South America.
Where Key Lime Pie Originated
Now for the controversial part: who created Key lime pie.
Gail Borden created condensed milk in the US back in the 1850s and it became more commercially available by the 1860s. In 1931, Borden (the company) published a promotional brochure with the recipe for a Magic Lemon Cream Pie in it (to help sell more condensed milk). Its basically an identical recipe that uses egg yolks, condensed milk, lemon juice and zest and has a meringue topping. Some say Florida locals and fishermen used local citrus to recreate the pie, and that’s how Key lime pie was created. The first published recipe for Key lime pie doesn’t show up until around 1940 though.
Another local legend states that a cook named Aunt Sally created the pie for her rich employer William Curry back in the late 1800s. Some of the story fits, as Key limes were just becoming popular back then, and refrigeration in the area wasn’t available yet, which made condensed milk popular. But without solid proof, we may never know for sure when and where Key lime pie made its debut. All that really matters though is that it’s pie and its awesome, right?
Ingredients for Key Lime Pie
The ingredients for Key lime pie are simple, but there’s also a lot of variations on how people make them and what is considered “traditional”. I’ll list the ingredients here, but also mention some alternatives below.
Graham Crackers – The crust here is a graham cracker crust, so you’ll need about 9 whole sheets that’ll be crushed. Alternatively in other parts of the world that don’t sell graham crackers, use digestive biscuits. 9 sheets of graham cracker is about 135 grams, so use that amount of digestive biscuits.
Sugar – I use brown sugar for the crust, but white sugar is fine too. I also use a small amount of confectioner’s sugar in the whipped topping.
Butter – You’ll need some unsalted butter for the crust, which doesn’t need to be at room temperature since you’ll be melting it.
Macadamia Nuts – The crust has a ½ cup of macadamia nuts that are crushed up and mixed with the graham crackers. If you have an allergy or simply don’t like them, just omit them, and add another 2-3 sheets of graham crackers instead (or about 165 grams of digestive biscuits).
Salt – The macadamia nuts I used were roasted but unsalted, so I added a pinch to the crust. If your macadamia nuts are salted, omit the extra salt.
Condensed Milk – For this recipe I use 2 14-oz cans of sweetened condensed milk for the filling.
Key Limes – You’ll need the zest from about 4 Key limes to make 2 teaspoons, and the juice from 30-35 Key limes to make 1 cup.
Lemon Juice – While Key limes are both sweet and tart, they can also be slightly bitter. To help tone done some of the sharpness, I add about 2 teaspoons of lemon juice as well.
Eggs – You’ll need 4 large egg yolks for the filling. Since you’re not creaming the eggs with butter and sugar, they don’t have to be at room temperature. If you’d like to make a meringue topping instead of whipped, reserve the egg whites also.
Heavy Cream – This recipe uses a whipped topping, so you’ll need about 1 cup of heavy whipping cream.
How to Make Key Lime Pie
Before going into the directions here I’d like to mention that some traditionalists will say that Key lime pie isn’t baked and only chilled. Technically, the eggs and condensed milk curdle when mixed with the lime juice, which is what thickens the pie, and the acidity of the lime juice somewhat “cooks” the eggs so that they shouldn’t make you sick. A lot of people actually prefer the texture of a baked Key lime pie though, and it eliminates any concern about the eggs, so that is the route I go here as well.
First, break out the food processor and a 9” pie plate or glass pie dish, and preheat your oven to 350°F/177°C.
Melt your butter and set aside. Break up the graham cracker sheets and toss into the bowl of your food processor along with the macadamia nuts and blend until mostly crushed into small pieces. Add the brown sugar, and salt if using, then pulse a few times to combine. Begin mixing again and slowly pour the melted butter in until fully combined and you have a moist mixture. You should be able to take a small amount and squeeze it between your fingers and it will hold its shape. If it feels too dry, add a little more butter, a tablespoon at a time, until it holds together and is moist but not wet.
If you don’t have access to a food processor, you can do this by hand instead. Toss the graham and nuts into a gallon size zipper lock bag and crush with a rolling pin or meat mallet until finely ground. Add the rest to the bag and agitate with your hands, or transfer to a mixing bowl and combine until the same consistency as above.
Transfer the crust mixture to the middle of your pie plate/dish and begin pushing down and out until the bottom is flat and the mixture is climbing up the walls of the dish. Using a flat-bottomed measuring cup helps to smooth out the crust and compact it, I believe I used a ½ cup measure in these photos.
Place the crust into your preheated oven and par-bake the crust for 8-12 minutes. When you can really smell the graham and nut aroma, the crust looks a few shades darker and feels mostly solid, it’s done. Remove from the oven and set aside. It doesn’t need to be completely cooled before adding the filling.
While the crust is par baking, begin making the filling. Using a nonreactive mixing bowl, whisk together the egg yolks with the Key lime and lemon juices. Add the zest and sweetened condensed milk and continue whisking until everything is combined and you can feel it slightly thickening.
Add the filling to the parbaked crust and return to the oven. Cook about 15-20 minutes, until the outside looks mostly set and the center has just a bit of jiggle to it. Remove from the oven and set on a cooling rack until room temperature. Once cooled, cover and transfer to the refrigerator for at least 1 hour, 3-4 hours or overnight is even better.
Once cooled, or just before serving, make your topping and decorations. Freeze a metal mixing bowl with the beaters of your hand mixer for at least 10-15 minutes. Add your heavy cream and sifted confectioner’s sugar and begin beating at low speed. Continue mixing and increasing the speed until you just hit the stiff peak stage. Top your pie with the whipped cream, I like to keep mine somewhat rustic, and add some freshly grated zest and a few slices of Key limes.
Key Lime Pie Alternatives & Quick Methods
Alternate Crusts and Toppings
As mentioned in the ingredients, many people have their own opinions on what is classic or traditional or authentic when it comes to Key lime pie. While this recipe uses a graham cracker and macadamia nut crust, you can also make a crust with just graham crackers, graham cracker and almond, graham cracker and pretzels, or a regular pie crust as well.
Toppings can be debated as well. Some will say tradition is a meringue topping, or a whipped topping, or no topping at all. The choice is completely yours and up to your preference. I also normally add a little vanilla extract to my whipped cream but opted not to here. While it gives a great flavor to whipped cream, I didn’t want the topping to have a competing flavor with the purity of the Key lime flavor in the pie. The added creaminess of the whipped cream does help mellow the tartness of the Key lime juice however, and I highly recommend it’s addition.
While the top and bottom of Key lime pie are sometimes hotly debated, the filling usually is not. Sweetened condensed milk, egg yolks, and Key lime juice are all you need. Zest is usually included as well, but I have seen alternatives that use sour cream or yogurt also. A good 90% or more of the time though, the filling is always the same.
Super Quick & Easy Method
If you’re trying to save money and/or time, there’s a few methods to streamline your pie. While I will always advocate for making everything yourself because it’s not difficult and healthier, sometimes you need a shortcut because life happens.
Buy a Premade Crust
Whether you want a pie crust or a graham cracker crust, both are readily available at all grocery chains. This will let you skip making a crust from scratch and the need to par bake it as well.
Buy Whipped Cream
Whether you get the whipped cream cans from the dairy section or some ready whip from the freezer section, you can save some time decorating by getting this ahead of time also and slathering it on just before serving.
Skip the Fresh Key Limes
Whether you buy a premade crust or a ready to use whipped topping, or both, you’ll still need to make the filling. If Key limes are difficult to find, you can also use regular limes. You’ll need the zest from 2 for the filling and the topping, but only around 8 limes for a cup of juice compared to 30-35 Key limes. The flavor and color will be slightly different however, and it won’t be a true “Key lime pie” when you use Persian limes instead.
Another alternative that will keep the color and flavor correct and is even easier would be to grab 1-2 limes just for their zest and get a bottle of Key lime juice. Nellie and Joe’s makes a great product and is available year-round at almost all grocery stores and online.
How to Store Key Lime Pie
Key lime pie needs to be refrigerated. When serving, don’t leave it sitting out for more than 2-3 hours before covering and returning to the fridge.
Cover the pie with plastic wrap or aluminum foil and you can store it in the refrigerator for 3-4 days. After that point you’ll probably notice some weeping (when the liquid ingredients start to break down and begin oozing out of the pie). If you notice a sour smell or taste, throw the rest out.
Alternatively, you can cover tightly with plastic wrap or aluminum foil and freeze for 2-3 months before the pie begins to degrade.
📋 Recipe
The Best Key Lime Pie
Ingredients
For the Crust:
- 9 sheets graham crackers, (See note #1)
- ½ cup macadamia nuts
- ¼ teaspoon salt, (If nuts are unsalted)
- 2 tablespoons brown sugar, packed
- 6 tablespoons unsalted butter, melted
For the Filling:
- 1 cup Key lime juice
- 2 teaspoons lemon juice
- 2 teaspoons Key lime zest
- 28 ounces sweetened condensed milk, (2 14-oz cans)
- 4 large egg yolks
For the Topping:
- 1 cup heavy whipping cream
- 1 tablespoon confectioner’s sugar, sifted
- Key limes sliced and zested for decorating
Directions
- First, break out the food processor and a 9” pie plate or glass pie dish, and preheat your oven to 350°F/177°C.
- Melt 6 tablespoons of butter and set aside. Break up the 9 sheets of graham crackers and toss into the bowl of your food processor along with a ½ cup of macadamia nuts and blend until mostly crushed into small pieces. Add the 2 tablespoons of brown sugar, and ¼ teaspoon of salt if using, then pulse a few times to combine. Begin mixing again and slowly pour the melted butter in until fully combined and you have a moist mixture. You should be able to take a small amount and squeeze it between your fingers and it will hold its shape. If it feels too dry, add a little more butter, a tablespoon at a time, until it holds together and is moist but not wet.
- If you don’t have access to a food processor, you can do this by hand instead. Toss the graham and nuts into a gallon size zipper lock bag and crush with a rolling pin or meat mallet until finely ground. Add the rest to the bag and agitate with your hands, or transfer to a mixing bowl and combine until the same consistency as above.
- Transfer the crust mixture to the middle of your pie plate/dish and begin pushing down and out until the bottom is flat and the mixture is climbing up the walls of the dish. Using a flat-bottomed measuring cup helps to smooth out the crust and compact it, I believe I used a ½ cup measure in these photos.
- Place the crust into your preheated oven and par-bake the crust for 8-12 minutes. When you can really smell the graham and nut aroma, the crust looks a few shades darker and feels mostly solid, it’s done. Remove from the oven and set aside. It doesn’t need to be completely cooled before adding the filling.
- While the crust is par baking, begin making the filling. Using a nonreactive mixing bowl, whisk together the 4 egg yolks with the cup of Key lime and 2 teaspoons of lemon juices. Add the 2 teaspoons of zest and both cans of sweetened condensed milk and continue whisking until everything is combined and you can feel it slightly thickening.
- Add the filling to the parbaked crust and return to the oven. Cook about 15-20 minutes, until the outside looks mostly set and the center has just a bit of jiggle to it. Remove from the oven and set on a cooling rack until room temperature. Once cooled, cover and transfer to the refrigerator for at least 1 hour, 3-4 hours or overnight is even better.
- Once cooled, or just before serving, make your topping and decorations. Freeze a metal mixing bowl with the beaters of your hand mixer for at least 10-15 minutes. Add your cup of heavy cream and 1 tablespoon of sifted confectioner’s sugar and begin beating at low speed. Continue mixing and increasing the speed until you just hit the stiff peak stage. Top your pie with the whipped cream, I like to keep mine somewhat rustic, and add some freshly grated zest and a few slices of Key limes.
Equipment Used
Notes
Your Notes
Nutrition
Meg
I mix the eggs and milk before adding the eggs because the lime juice can "cook" the egg yolk and make the recipe harder to blend.
Toni V. Jensen
This is a REAL key lime pie recipe! There condensed milk and egg yolks curdle! Some terrible recipes use cream cheese! 😵🤢🤬 I use the 4 egg whites to make meringue cups.
I like the homemade whipped cream for the topping! I do use bottled key lime juice that you named!
Sun
Such an awesome pie!