Learn to make the best key lime pie with a buttery graham cracker crust, a tangy and creamy key lime filling, and a perfectly fluffy whipped cream topping!
I hesitate to call any recipe the “BEST” because there are so many different food palates and taste preferences. What I may think is the “best” someone else could think is just “okay”.
However, I really believe this is the Best Key Lime Pie!
This recipe for the Best Key Lime Pie starts with a homemade, buttery, sweet, graham cracker crust. Then, it’s filled with a rich, tart, creamy, and tangy key lime filling. Finally, it’s topped with a fluffy whipped cream that perfectly balances out the other flavors in the pie.
Best Key Lime Pie Ingredients
Buttery Graham Cracker Crust
Homemade graham cracker crusts will taste much better than buying store bought graham cracker crusts. Plus, they are easy to make! This crust uses less sugar than many other recipes, so it’s not too sweet.
If you do want a shortcut, you could buy graham cracker crumbs instead of crushing them yourself.
To make graham cracker crumbs, add one sleeve of graham crackers to a blender or a food processor, and pulse until finely ground. Alternatively, you can also add the graham crackers to a plastic baggie, and crush the graham crackers with a rolling pin until finely ground.
In a large mixing bowl, combine graham cracker crumbs, sugar, and melted butter until the mixture is fully combined.
TIP: Use a measuring cup to easily press crust mixture evenly onto the sides and the bottom of the 9.5″ pie plate.
Bake pie crust for 8 minutes at 350 degrees until the crust is just set and golden brown. Allow the pie crust cool for 30 minutes before adding filling.
Creamy and Tart Key Lime Filling
For this recipe, you will need 3/4 cup of lime juice. For authentic Key Lime Pie, you will need to use the juice from key limes. However, the juice from regular limes can be used as well.
Key limes tend to be smaller and have less juice than traditional limes found at the grocery store. If you are lucky enough to find fresh key limes where you live, you will need twice as many key limes than you will need if you use traditional limes.
Since key limes tend to be much more expensive than traditional limes, and because they can be a pain to juice, I prefer to use bottled key lime juice. It can usually be found next to the regular lime juice at your local grocery store.
Because I prefer to use bottled key lime juice, I like to add the juice and zest from a few fresh limes to give the pie freshness and brightness.
TIP: Be sure to clean the outside of your limes very well before you zest or cut them! If you do not clean the outside of the limes, any bacteria on the outside of the fruit may end up in your filling. Reduce this risk by washing your fruit!
TIP: Zest your limes before you juice them. It will be much more difficult, if not impossible, to zest your limes after you juice them.
TIP: To get the most juice out of each lime, microwave the whole lime for about 20 seconds. Rolling the limes on the counter beneath your hands will also help release even more juice.
Sweetened Condensed Milk
Sweetened condensed milk is a very common ingredient in key lime pie. It is made by removing water from the milk and adding sugar (as a preservative). If it is not opened, canned sweetened condensed milk can last for years without refrigeration.
Sweetened condensed milk is used in this recipe as a thickener and to add sweetness to the pie.
Feel free to use store bought or homemade sweetened condensed milk in this recipe.
Using sour cream adds richness, creaminess, and thickness to the pie. Likewise, the sour and tangy flavor of the sour cream pairs well with the tart and tangy flavor of the lime juice.
TIP: To reduce the calorie count, use light sour cream instead of regular sour cream.
Fluffy Whipped Topping
This recipe for the best key lime pie needs whipped cream to balance the tartness and sweetness from the filling and the crust. It will not taste as good if you leave it off!
Just like the graham cracker crust, spending a few extra minutes making your own whipped cream topping will always taste much better than buying store bought whipped topping.
Using a stand or hand mixer, whip heaving whipping cream, powdered sugar, and vanilla until soft peaks form.
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Best Key Lime Pie
Graham Cracker Crust
- 1 ½ cups Graham Cracker Crumbs (1 Sleeve Crushed)
- ⅓ cup Sugar
- 6 tbsp Salted Butter, Melted
Key Lime Filling
- 28 oz Sweetened Condensed Milk
- ½ cup Sour Cream
- ¾ cup Key Lime Juice
- 2 Limes (or 4 Key Limes)
- 1 cup Heavy Whipping Cream
- ½ cup Powdered Sugar
- 1 tsp Vanilla
Graham Cracker Crust Preparation
- Preheat oven to 350°.
- Pulse graham crackers in a blender or a food processor until finely ground. -OR-Alternatively, add graham crackers to a plastic baggie and crush with a rolling pin until finely ground. -OR-Or substitute store-bought graham cracker crumbs.
- In a large mixing bowl, mix graham cracker crumbs, sugar, and melted butter until the mixture is fully combined. Evenly, press mixture into the sides and bottom of a 9.5" glass, pie plate.
- Bake pie crust for 8 minutes. Let pie crust cool for 30 minutes before adding filling.
Key Lime Filling Preparation
- With water, wash and clean the outside of the limes. Finely zest the limes with a zester or on the smallest holes of a grater.
- Roll the limes on the counter, beneath your hands, to start to release the juices. Slice the limes in half with a sharp knife.
- In a large mixing bowl, whisk together sweetened condensed milk, sour cream, key lime juice, and the zest and the juice from the fresh limes.
- Pour filling into prepared graham cracker crust, and bake at 350° for 10 minutes.
- Let pie cool at room temperature for 15 minutes. Then, refrigerate pie for at least 3 hours.
Whipped Topping Preparation
- Using a stand or hand mixer, whip heaving whipping cream, powdered sugar, and vanilla until soft peaks form.
- Top pie with whipped cream, serve, and enjoy!