Key Lime Pie: demystifying a classic

If you read this blog regularly, you’ll know that we’ve taken some flak lately about nonconformist interpretations of traditional treats. Namely, challah, bialys, and Black and White (a.k.a. Half Moon) cookies.

I’m not complaining; I love to generate friendly controversies around baking. After all, it’s more fun to disagree over the correct method for frosting Black and White cookies; or the amount of onions in the center of a bialy than, say, the merits of Congress’ latest health-care plan.

Still, it’s with trepidation that I publish this recipe for Classic Key Lime Pie. I KNOW there’ll be residents of Key West who decry my use of anything other than fresh Key limes. And there are those who insist Key lime pie should be topped with meringue, not whipped cream. And that a graham cracker crust is an invention of the devil himself.

Well, let me tell you something: I began my quest for REAL Key lime pie assuming the classic version would NOT feature a filling based on sweetened condensed milk.

I was sure that someone, somewhere – Southern Living magazine? Paula Deen? – would offer me the original Key lime pie recipe, the Mother of all succeeding generations. Surely the true version must be custard-based, or at least lemon meringue-pie like.

Well, guess what? I was wrong. REAL Key lime pie, which first appeared prior to the Civil War, was a direct result of the Borden company’s invention of sweetened condensed milk. Southern cooks, wanting to take advantage of this great new product, added lime juice, poured it into a pastry crust, and baked up what was destined to become one of America’s favorite pies.

Pecan pie, another candidate for the Southern Baking Hall of Fame, had a similar provenance. It was invented in the 1930s by the wife of a Karo sales executive, to showcase that company’s signature syrup.

So I’m throwing down the gauntlet. You can claim that your great-grandma’s recipe for Key lime pie makes the one and only original, classic, true and REAL Key lime pie. But I’ll counter with this information from one of my favorite Web sites,

“Key lime pies were first made in the Keys in the 1850s. Jean A. Voltz, in The Flavor of the South (1977), explains that the recipe developed with the advent of sweetened condensed milk in 1856. Since there were few cows on the Keys, the new canned milk was welcomed by the residents and introduced into a pie made with lime juice. The original pies were made with a pastry crust, but a crust made from graham crackers later became popular and today is a matter of preference, as is the choice between whipped cream and meringue toppings.”

And that’s my last word on the subject. At least till your comments start coming in…

OK, enough with the history lesson. Let’s make Classic Key Lime Pie.


Ah, here it is, the progenitor of I wonder how many hundreds of thousands of Key lime pies since 1856… Borden’s sweetened condensed milk. Thanks, Elsie!


Next, lime juice. Use fresh Key lime juice, if you can find Key limes. (And no, I’m not going to get into an argument about whether all the “true” key lime trees in Florida were destroyed in the hurricane of 1927.)  Bottled Key lime juice is an option, too.


And then there are good ol’ supermarket limes: Persian limes, of which “Susie” here is a nice, fat, juicy example.


If you love-love-LOVE lime, lime oil should be a permanent resident of your fridge. It heightens the lime flavor of anything lime. Plus, it’s a key ingredient in the BEST lime cookies


Now, talk about nonconformist – coconut in Key lime pie? Not exactly IN the pie, but toasted coconut added to the graham cracker crust is tasty indeed.

OK, let’s jump in. First, select a pie pan whose inside top dimension is at least 9″, and whose height is at least 1 1/4″. Preheat the oven to 325°F.


Next, get out your graham crackers. You’ll need 9 crackers. There are usually 10 or 11 crackers in one sleeve, so have yourself a s’more with the extra(s).


Put the crackers into your food processor with 1/4 cup confectioners’ sugar, and 1/8 teaspoon salt.


Add 1/4 to 1/3 cup toasted coconut, if desired, for that tropical touch.


Process until the mixture is pretty finely ground.


Add 1/3 cup melted butter…


…and process until the crumbs are moist and beginning to clump together.


Pour into your pie pan. I’ve selected a stoneware pan here.


Use your fingers or, more effectively, the flat bottom of a measuring cup to press the crumbs into the bottom of the pan.


Use the side of the cup to press the crumbs against the side of the pan.


Your finished crust should look fairly smooth, like this.

Bake the pie crust for 15 minutes; it’ll start to darken in color a bit. Remove it from the oven, and place it on a rack to cool while you make the filling.


WHAT are these limes doing in the microwave? Rumor has it that heating them briefly softens their interior membranes, allowing them to release more juice.


I did the test; didn’t seem to make much difference. But the softened lime did feel easier to squeeze.


Before you squeeze the juice out of all the limes, shred the peel off one of them. I’m using a microplane zester here; it works very well indeed. Microplane definitely makes sharp, efficient graters.


One lime should yield about 3 tablespoons (not packed) of zest. Don’t stress about a bit more or less.


Put the zest and 3 large egg yolks into a mixing bowl.


Whisk the zest and egg yolks at high speed of an electric mixer for about 4 minutes. The mixture will lighten in color and thicken somewhat, looking kind of like Hollandaise sauce.


Stir in one 14-ounce can of sweetened condensed milk, mixing till smooth. Beat at high speed for 3 minutes; the filling will become slightly thicker, and gain a bit of volume.


Add the 2/3 cup lime juice, stirring just to combine. The mixture will thicken. Add lime oil to taste, about 1/8 teaspoon. Keep in mind that real or bottled Key lime juice is generally more potent/sour than Persian lime juice, so you probably won’t need as much (or any) lime oil if you’re using Key lime juice.


Pour the filling into the crust.


Smooth it out, if necessary.


Bake for about 25 minutes, till it appears set around the edges, though still a bit wobbly in the center. The center should read about 145°F on an instant-read thermometer. You’ll want to add strips of aluminum foil, or a pie crust shield, after about the first 15 minutes, to prevent the edges from over-browning.


Remove the pie from the oven. It will have puffed up a bit, and it’ll gradually settle as it cools.


Let the pie cool to room temperature. Refrigerate for several hours before serving. Slice and serve each piece with a lightly sweetened dollop of whipped cream, if desired. (I eschew whipped cream. Not because it’s untraditional; but because I take my KLP straight.)

BTW, garnishing with whipped cream is not heresy. What you do in the privacy of your kitchen is nobody’s business but your own. Cool Whip, Reddi Wip, Ben and Jerry’s Chunky Monkey – heck, it’s all good.


P.S. No-bake Key lime pies were popular as early as the 1940s. So if you worry about egg yolks, or simply prefer an easy no-bake filling, try this cream cheese/condensed milk Key Lime Pie.

Read, rate, and review (please!) our recipe for Classic Key Lime Pie.

Buy vs. Bake
Buy: Max’s Deli Café, Boston: slice of Key Lime Pie, $2.75

From the supermarket freezer case: Edwards Pie Singles, 3 1/4-ounce slice Key Lime Pie, $1.40

Ingredients: Reduced Fat Sweetened Condensed Milk, Water, Partially Hydrogenated Vegetable Shortening (Palm Kernel Oil, coconut Oil, Soybean Oil), Enriched Flour (Flour, Niacin, Reduced Iron, Thiamine Mononitrate, Riboflavin, Folic Acid), Sugar, High Fructose Corn Syrup, Egg Yolks, Contains Less than 2% of Each of the Following: Lime Juice Concentrate, Food Starch-Modified, Baking Soda, Salt, Dextrose, Artificial Flavors, Sodium Citrate, Lime Juice Concentrate, Lime Pulp, Polysorbate 60, Soy Lecithin, Sodium Caseinate (a Milk Derivative), Carbohydrate Gum, Polyglycerol Esters of Fatty Acids, Colored with Beta Carotene, Xanthan Gum, Disodium Phosphate, Lime Oil, Lemon Pulp Cells, Lemon Oil, Sorbitan Monostearate, Guar Gum.

Bake at home: 3 1/4-ounce slice Classic Key Lime Pie made with Key lime juice, 99¢; made with fresh lime juice, 66¢

Ingredients: graham crackers, confectioners’ sugar, salt, butter, lime juice & rind, egg yolks, sweetened condensed milk, lime oil.

PJ Hamel

PJ Hamel grew up in New England, graduated from Brown University, and was a Maine journalist before joining King Arthur Flour in 1990. PJ bakes and writes from her home on Cape Cod, where she enjoys beach-walking, her husband, two dogs, and really good food!


  1. Rebecca

    Is that 1/3 cup butter the volume before or after melting? It seems like 1/3 cup chilled would yield less after melting but I may be wrong. Thanks!

    1. PJ Hamel, post author

      Rebecca, butter actually measures the same both solid and melted; so it’s 1/3 cup either way. Thanks for asking – good question. PJH

  2. Jan Marrie

    Thanks, we tried your pie and liked it very much, you sure have the nack for key lime pie. However our favorite key lime pies have to be the ones that Anita Pelaez and her husband Kutchie have been baking for thirty something years. We visited their key lime pie factory about seven years ago after checking-out the Biltmore House down the road. What a fantastic couple they truly are. Husband and wife working team for so long, it is truly amazing. Their factory and grill is a must see destination. We highly recommend that anyone that loves great food and has a desire for some authentic key lime pies, just try-out the Masters of Key Lime Pies, Anita Pelaez and her husband Kutchie. Together they work hand and hand to bake the finest. You’ll see!…..Jan Marrie

  3. Monthannah

    oodI was wondering if lime oil is better than lime juice , isn’t natural better? I have never tried lime oil. Is the taste the same? Let me know. Thanks
    Lime oil is used in addition to accentuate the lime juice in this recipe. It is a very potent oil, which is why only 1/8 tsp is used. You could not substitute oil for the juice, as it would not provide the acidity which is necessary for the tangy flavor of this pie. And the oil is just as good as the juice. It comes form the pores of the outer lime peel and contains the same flavor properties that would be provided by lime zest. ~Amy

  4. joane

    just got the catalog with the KLM slice on the front…my co-workers knowing of my KLM addiction, had a local chef make one with the pretzel crust that is featured in the catalog OMG OMG!!!!!! to die for!!!!!

  5. Carly Simon

    Hey, I Know Kutchie Pelaez and his World’s Greatest Key Lime Pies, Kutch also
    is Famous for his Awesome Cheese Burgers. James and I Used to hang-out with Kutch and a bunch of others back in the 60’s and 70’s.
    Kutch opened his restaurant back in the 70’s and has been making those awesome Key Lime Pies ever since. If you have ever tried the KLP that Kutch makes then you already know why they have become World Famous. Their just Awesome to say the Least.
    Kutch even grows his own Key Limes on some property that he has down in
    Florida. He told me that whenever he picks them his self that he always gets
    cut-up from all the thorns on his trees. As many pies as he probably sells by-now, I’m sure that he is not growing all that he needs anymore.
    We haven’t been in touch with Kutch in several years now but I’m sure that
    he is still at it. If you should go by kutchie’s be sure to try his key lime pie and tell him Carly said hello, give him a big huge for me.

    …………………..thanks, ……Carly S

    Thanks for sharing the history of the famed pie and pie maker! Irene @ KAF

  6. Dianne Darby

    We don’t make it but we sure like to eat it. It is our favorite sweet treat of them all. We try it every where that we travel. The best that we have ever
    eaten was at an island themed place down south in Asheville, NC. We were
    told at the chamber of commerce that this place serves The Would’ Greatest
    Key Lime Pie and that’s all we needed to hear to go over and give them a try.
    The name of the restaurant is Kutchie’s Key West Kutcharitaville Cafe…………
    Their Reputation is well deserved. Kutchie’s Key Lime Pie is really the best that we have ever eaten out of the thousands that we have tried in fifty years
    of travel. Theirs is very different from all the others. It is in a very good crust,
    not cracker crumbs. The pie is very thick, not shallow like many others. The pie isn’t green like many others, it is a mellow yellow in color. It is topped with fresh whipped cream. Just the Best key lime pie in the whole world. I wish everyone could try it someday………………………………………………………..
    …………………………………….Dianne Darby, Vermont

  7. sherry baines

    i will try the yummy key lime pie. when in texas years ago they served their key lime pie with drizzled raspberry sauce and chocolate drizzled on the plate and fresh raspberrys and fresh whipped cream. I will try to duplicate this with your recipe. i have a raspberry garden to die for, now working on blackberrys. thanks for your website. do you have a yummy lemon pie recipe as that is also an art to make. sherry b.

    Hi Sherry – Try our classic lemon chess pie, with or without its strawberry topping; or our lemon meringue pie. Not sure which kind of lemon pie you were looking for; both are tasty. Enjoy – PJH

  8. Joanne Libby

    I made your recipe for key lime pie yesterday and found it to be horrible. I know I shouldn’t make anything with sweetened condensed milk, but this recipe came from the King Arthur people so I thought it might be good. Both my husband and I thought it tasted pasty. Even the crust was not good. This was the first time I made graham cracker crust with confectioner’s sugar and it turned out heavy and too sweet. The only good part was the whipped cream we topped it with. Sorry.

    Yes, Joanne, I’m sorry, too – that it didn’t work out well for you. Sometimes things just aren’t to our particular taste, are they? Glad the whipped cream helped salvage a bad experience… PJH

  9. Lish

    Finally made the pie, huge hit! I also made the lime cookies today, and I made them mojito. I followed the recipe for the dough, and for the topping, I used mint flavored granulated sugar with some rum flavoring that I whirred in the blender till fine powder. A wonderful mojito cookie. And I finally used up the mint flavored sugar I made last year!

  10. Oonagh

    To Nicole who wanted a recipe for Rum Cake. We went to Bermuda a few years ago and I had looked up Island food to see what to check out. You’re right, all the recipes on line, plus ingredients listed on back of actual Bermuda Rum Cakes made and sold on Bermuda, all start with a packet mix. As a chef and instructor I have always cooked from scratch. So I took my pound cake made with cream cheese and butter, added rum (actually Bermuda Gosling’s rum) plus pecans, baked in a bundt pan then topped with a butter, light brown sugar and rum glaze when it came out of the oven . Fabulous but don’t light a match near it. I can e-mail recipe to Susan at KAF if people want me to.

    by all means, Oonagh. Thanks. Susan


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