4.97 from 27 votes

Key Lime Pie

By Sam MerrittPublished Jul 17, 2024

116 Comments

Servings: 10 servings

4 hrs 40 mins

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This classic, easy key lime pie recipe is a refreshing treat! Start with a simple homemade graham cracker crust, fill it with a 3-ingredient key lime filling, and finish with a slightly sweetened, fluffy whipped cream. Recipe includes a how-to video!

Key lime pie that's been cut into slices and topped with whipped cream swirls.

My Favorite Key Lime Pie

Today I’m resharing a classic family favorite: key lime pie!

Possibly one of the most extensively tested recipes on my website (beside my macarons), this recipe is a no frills version; just a simple and easy pie with a crumbly graham cracker crust, a creamy filling with a tart lime bite, and a fluffy, sweet homemade whipped cream topping.

Slice of key lime pie with one bite that's sitting on a fork beside the pie.

Why Try My Recipe:

Definitively tart, without making your mouth totally pucker — you need to be able to eat the whole slice and some pies are so tart I can’t make it past one or two bites! You’ll be able to finish a whole slice (then maybe another!) of this one.
Easy to make. When things can be simple, they should be. There’s no need to complicate a classic with fussy ingredients or awkward techniques. This recipe is well-loved because of how simple it is, we stick to classic ingredients but make a few ratio tweaks to yield the absolute best, most balanced flavor.
Simple, refreshing, and timeless recipe.
Extensively tested. I made dozens of versions of this pie before settling on the version that you see here today. I first shared this recipe in 2015 and it’s been popular and well-loved ever since. When I planned to reshare it, I even went back to the drawing board and tried to improve on this recipe, and half a dozen pies later decided it’s truly just perfect as written.

Four key lime pies with slice missing from each — A look at just one of many rounds of blind taste-testing.

What You Need

None of these will surprise you, we’re using classic ingredients And PLEASE, pay attention to my notes on condensed milk!

Overhead view of labelled ingredients including condensed milk, lime juice, eggs, and more.

Sweetened condensed milk. Do not use evaporated milk! While the two are sold next to each other and look similar, they are not the same (you’ll know this if you’ve made my easy fudge or no-churn ice cream). My recipe uses 2 cups of condensed milk, which is typically about 1 1/2 cans. Sure it would be nice if we could just use an even 1 or 2 cans, but as I mentioned above, you get the best results when you use this slightly awkward measurement. Use the leftover as a coffee creamer or topping for shaved ice!
Key lime juice. If you’ve made my key lime cake or watched the video, you’ve heard me complain about my inability to find fresh key limes where I live. It’s just rarely possible. While I’ve tested this recipe with fresh key limes and prefer it that way, I also can confirm this pie works perfectly well with bottled key lime juice (not regular lime juice, which doesn’t have the same flavor). “Nellie & Joe’s” brand is the one I use, it’s usually available in the juice section of most grocery stores.
Butter. You can salted or unsalted butter in the crust, but I tend to prefer salted to help balance out the sweetness of the pie. If you don’t have salted butter, you can add a scant ¼ teaspoon of salt with the butter.
Brown sugar. To give my graham cracker crust extra flavor, I like using a combination of brown sugar and granulated sugar. Either light brown or dark brown sugar will work.
Egg yolks. You will need six egg yolks. Room temperature eggs will combine easier, so that’s what I recommend using.
Vanilla extract. This goes into the whipped cream, not the actual filling of the pie. You don’t want it directly in the filling, it would diminish the bright key lime flavor.

SAM’S TIP: If you don’t want to waste the egg whites, save them to make my coconut cake, lemon cake, strawberry cake, meringue cookies, chocolate meringues or French macarons.

This is just an overview of the ingredients I used and why. For the full recipe please scroll down to the bottom of the post!

How to Make Key Lime Pie

Juice your limes (or measure out your lime juice!). Since they are so small, I use a garlic press to squeeze my key limes. If you can’t find key limes in your area (they are so hard to find!), bottled key west lime juice is the best substitute I’ve found. I’ve made this recipe several times with the juice pictured above, and I never have an issue.

pressing graham cracker crumbs into crust

Make the graham cracker crust. Combine your graham cracker crumbs and sugars, then stir in the melted butter until everything is coated. Pour this mixture into your pie pan and use a measuring cup to press it into the bottom and up the sides. Set this in the fridge while you prepare your filling.

Add the filling and bake. Whisk together the condensed milk and egg yolks, then add the lime juice. Whisk until you notice the mixture has thickened a bit (or at least whisk vigorously for 30-60 seconds and make sure everything is nice and uniform), then pour into your crust and bake.

Overhead view of a pie that's been cut into slices and topped with swirls of whipped cream and lime zest.

Cool and decorate. Let the pie cool to room temperature, then place in the fridge to chill for 6 hours or overnight. Once chilled, decorate as desired (I like to add a whipped cream border and lime zest!).

SAM’S TIP: While I recommend using key lime juice for the filling, you can use regular lime zest for a garnish. That small amount won’t make a difference flavor-wise.

Frequently Asked Questions

Can I use regular limes?

I don’t recommend it. Key limes aren’t just smaller and more obnoxious to squeeze than regular limes, they also have a different acidity and flavor to them While some people will argue that you can substitute lime juice for key lime juice, it’s just not my preference or recommendation.

If you can’t find fresh key limes (I often can’t), you can substitute bottled key lime juice. I personally like to use Nellie & Joe’s brand (I have no affiliation with them), they sell Key West lime juice as well as 100% key lime juice. Either will work wonderfully.

How long will the whipped cream hold its shape?

Unlike store-bought whipped creams, the homemade whipped cream in this recipe will hold its shape for several days in the fridge. You don’t have to worry about any weeping or softening!

Why isn’t key lime pie green?

While limes and key limes are green on the outside, you’ll notice their juice isn’t. The color of the pie reflects the natural color of the key lime juice combined with yellow egg yolks and white(ish) condensed milk. When made properly, it should have this more yellowish color. Green key lime pie is usually made using food coloring.

Can I just use 2 cans of condensed milk?

Nope! OK, I mean technically the pie will still “work”, but the consistency isn’t as nice and the flavor isn’t as vibrant or pleasant. After extensive (and I do mean extensive!) research, I found that 2 cups of condensed milk was the perfect amount for the perfect taste and texture. And as someone who likes to use neat and tidy measurements, I really did try to leave you with a solid recipe that used a neat 2 cans, but it just wasn’t as good as this version!

If you love key lime pie, try my lemon pie next! It’s similar to this recipe, but definitely worth a try for something a bit different.

Enjoy!

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This recipe was originally published 06/22/2015, photos and text updated. Not the recipe, though, that was evidently just right as written and remains the same, albeit with a few additional (hopefully helpful) notes.