The Key to Key Lime Pie

What is the key? Mexican limes! The truth is that "Key limes" and "Mexican limes" are the same lime and, according to my panel of experts (Mark), they are from neither Mexico nor the Florida Keys, but are an exotic introduction, originally native to Southeast Asia.

Over many centuries, they were introduced across South Asia, through the Middle East to North Africa, on to Sicily and Andalusia, and then via Spanish explorers to the West Indies, including the Florida Keys. From there, their cultivation was disseminated outward across tropical and subtropical North America, including Mexico, Florida, California, and, of course, Arizona.

When ripe, they are yellow but, unless you grow them yourself, you see only green ones sold in stores. The ones I used today are from our local grocery, where they are plentiful and inexpensive! I paid $1 for two pounds; other stores have them 20 for $1.

If you have never seen a Mexican lime (I can't call them Key limes while living here in the Southwest), they are much smaller than regular limes - about 1 to 1 1/2 inches in diameter. They have a higher acidity, which gives this pie it's unique tartness. Once I had had a Key Lime Pie made with fresh Mexican limes, there was no going back to the bottled stuff (apologies to Nellie and Joe - yet with many thanks to them for making key lime juice available to millions of people everywhere).

If I weren't able to get fresh Mexican limes, I would use about 2/3 regular lime juice and 1/3 lemon juice to increase the acidity.

My first Key Lime Pie slice? It was at a Bob's Big Boy in Florida when I was 12 years old, on holiday with my friend Michael and his mother, Nan. I came back from that trip and nagged my mother to make me a pie for my birthday. Poor Mom... This was before the Internet and Key Lime Pie was pretty exotic for a suburban Philadelphia family. Eventually, she found a recipe and made it for me, but used a drop or two of green food coloring because she thought it should be green. Key Lime Pie is pale yellow.

This is the best kind of juicer for juicing many little limes!
Toppings? Some people use a meringue, some choose whipped cream. If forced, I would choose the whipped cream, but I generally prefer it without a topping, or just a small dollop of whipped cream.

Crust? Somehow, a graham cracker crust is the norm, but my first slice was with a butter pastry, and that remains my preference. (I used this quick and easy Food Processor Butter Crust today)

Upgrades? You can gussy it up a bit if you want. I like to fill the shell with either blueberries or raspberries before adding the custard. And, if making a crumb crust, try adding a teaspoon or two of ground ginger, or simply use ginger snaps in place of graham crackers.

In the good ol' days of safe eggs, the custard was not cooked; it thickened on its own while in the refrigerator. Today, I bake the pie for about 10 minutes to make it safe for all... and baking helps it set nicely.

About the pie tin. Mom had some of the most amazing old pie and cake tins. This Ovenex® tin is one of my favorites. I have four cake tins to match.

So, whether from Mexico, the Florida Keys, Asia, or Arizona, if you can grab some of these limes, do so ... and pucker up for a great slice of Key Lime Pie!

~ David

Key Lime Pie

1 pre-baked 9-inch pie or tart crust, cooled
1 14-ounce can sweetened condensed milk
4 egg yolks
1/2 cup fresh key lime juice (I squeezed 33!)

Preheat the oven to 350°F.

Whisk the sweetened condensed milk, egg yolks and lime juice together until smooth.

Pour into the prepared crust and bake for 10 minutes.

Remove pie from oven, let cool, and then refrigerate until ready to serve.

Serves 6-8.

Notes: when the limes are in season, they are juicier and fewer - perhaps 20 - would be required to make this pie. I live the Cuisinart juicer for times like this - much less stress on your shoulder form juicing!


  1. I have never tasted a real key lime, so I don´t know about the exact flavor, which is a shame, because we get two types here, the small green ones used for caipirinhas (brazilian cocktail that we drink like here like it´s our last day)and what they call subtle lemons. These last ones tend to turn yellowish in time.
    Love your pie, so easy and perfect with nothing on top! And such a crowd pleaser. Have a great sunday!

  2. Paula - I wonder if the ones you use for the caipirinhas are the same... How big are they? Mark nd I love caipirinhas and spent several hours looking for our first 10 years ago in NYC. Finally, we found a Brazilian restaurant and had one. Very tasty!

  3. David, they are pretty small, like a big golf ball. Then there are others that are round but like a very small lemon. I like to mix either with lemon juice for the lime pies.

  4. When we used to spend a couple of weeks a year at our place in Key West, we'd sample a different version of Key Lime Pie every time we went out to dinner - my favorite was always the simplest, and I've gotta say that I'm partial to the graham cracker crust!!

  5. Paula - these are even smaller than your little limes! It really makes me wonder why they aren't available down there!

  6. Corbin - I will definitely keep your preference for graham cracker crust in mind! You know, I have not had Key Lime Pie in Florida siècle I was a boy. I imagine it is much better now than then.

  7. Gorgeous post as per usual David! I've never tasted a Key lime either. Tahitian limes are most commonly sold in the local markets here, alongside occasional Kaffirs (more treasured for their leaves than the juice as you most likely know!). I LOVE that pie tin. It's beautiful! Unfortunately my mother doesn't own anything that interesting... all of my tins are rather new springform or freeforms from the local kitchenware store. I'll have to scour a few more markets. Beautiful tins make the experience of baking even better, I think!

  8. Laura - your Tahitian limes are the same as our Persian limes. If you want to approximate a Key lime pie, fill your half-cup measure about 2/3 full of Tahitian lime juice and then the rest with lemon juice. I love using kaffir lime leaves in cookin and will add the zest to coconut rice, but rarely use the juice.

    As for finding tins, I have had the most luck on eBay! Good luck!

  9. My brother has a few lime trees and often gives me limes to take back to New Hampshire. They are yellow (so I have to keep them separate from the lemons he also gives me)--I did not know why they were yellow! Always learning something from you and your posts!

    The pie looks delicious. I, too, like the pastry crust version.

    I love the pie pan. My mother also had some pans like that. I have neither seen them in years nor thought of them--I wish she still had them!

    I know we will make that pie soon!

  10. This looks amazing, I love key lime pie. So refreshing. I was going to mention persian limes but looks like Laura already beat me to it :)

  11. Susan - I was looking on eBay recently and found quite a few of these tins readily available and no expensive at all. It is nice having the fresh limes, especially when they are from your brother. I once made a macadamia nut crust for a key lime pie - and since your brother has those, too, I am thinking it is a natural combination next time you visit...

    Ahu - I love Persian limes and grown them - they are so flavorful and sweet!

  12. Ok, so I didn't know the history of these li'l key limes. Very interesting, D.
    And I love the recipe.
    Except for juicing, it's a snap!

  13. Colette - you are right! The right squeezer makes all the difference. I love the one I have from Cuisinart - it was pretty easy!

  14. I didn't know about different kinds of limes! I just go to the shops and buy 'a lime', perhaps I should try some others (: I love key lime pie so I'll have to test this out
    from Emily x

  15. I know, Emily - so many limes, so little time!And the fun part is that they are all good! Hope you like the pie.

  16. David, so there I was thinking I'd never make a true key lime pie with the regular limes I get at regular supermarkets here in Australia. Now I know I can go to Chinatown and pick up the imported SE Asian ones at the shops there. And they're much cheaper!

  17. John - well ain't that the kicker? Yes, they cost almost nothing here, too - and they are so good!

  18. David, I love this post, learned a lot about limes - I read this before I left to do my grocery shopping this morning and there I was in my favorite fruit store about an hour ago staring at those "Persian Limes" from Mexiko and thinking about this Key Lime Pie of yours - I have made a few Lime Pies before but I was never really content with the way they turned out, so I will most definitely try out your recipe. I also adore vintage cake molds and tart pans of all shapes and sizes - I collect them and use them as much as I can! What a wonderful post! I am so very glad to have this blog and enjoy my "stays" here!
    Noch einen schönen Tag und liebe Grüße aus dem sehr sonnigen Bonn! Andrea

  19. Vielen Dank, Andrea! I pretty much love any citrus cake or pie - always my go to dessert! Although, the are a few German cakes and tarts that turn my head - stachelbeer kuchen is one I had in Heidelberg many years ago... Ausgezeichnet! Whenever I travel in Europe, I always look for antique baking tins, spoons, bread boards and such... and just unusual cooking gadgets like the one for making spätzle. It's a lot of fun! Thanks again for visiting! Bis bald!

  20. Every time I come to your site I learn something new! I always wondered why my limes turn yellow... well I have a tree full of ripe limes at the moment so I will be trying this recipe :) Have a great day!

  21. Karen - with Mark in the house, I am always learning something new. Actually, a lot of the fun of blogging has been doing research on the subjects! That is a sided benefit I didn't expect. Let me know how your pie comes out!


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