My relationship and love for Key Lime Pie began in the 1980s when I gave Cuisinart food processor cooking classes all over Florida—two two-hour classes a day. After the evening class, dinner time. At just about every restaurant I went to, Key Lime Pie appeared on the menu. And I always ordered it. All were delicious, and nary a crumb survived. Each restaurant kitchen made its pie in pretty much the standard way: stir together egg yolks with sweetened condensed milk, and finish by mixing in fresh lime juice. The acidic lime curdles the milk proteins and sets the filling. Key limes aren’t any limier than the ubiquitous Persian lime, but the name Key Lime somehow just sounds romantic. Oh, and all the pies I sampled sported Graham cracker crusts.
All or almost all key lime pies these days are made with Persian limes. Nevertheless the name “key” is still used because it is an unprotected designation.
Many different citrus species thrive in Hawaii, including lemons and the common Persian limes. Another lime that we go nuts over is the Calamansi lime. Native to the Philippines, these limes thrive in many tropical and subtropical climates. They grow on trees and are seasonal. The fruit is orange or green or somewhere in between, but the juice is always bright orange. Calamansi is a seedy fruit, but there’s more pulp to seed, so they’re juicy

At a farmers’ market in Lihue a couple of years ago, one seller had nothing but calamansi limes to sell. Visitors didn’t know what they were, but when asked, the seller said, “key limes,” and in short order all were sold.
I use calamansi limes in my key lime pies. If you live where these limes don’t, do not despair. My way of making the filling assures it will feel super creamy regardless of the lime; but the calamansi lime adds a certain depth of tang the key lime or Persian lime lacks.
I do not use a graham cracker crust for this pie, and I recommend you don’t either. A graham cracker crust is convenient, but its taste and texture just get in the way of the heavenly filling. A baked pie crust—homemade or store-bought--is the way to go. And, historically, key lime pie originated long before the Graham cracker crust was born. So a true pie crust is the original base for this pie.
Here’s the filling recipe:
4 large egg yolks
1/8 teaspoon salt
1 can (14 ounces) sweetened condensed milk
½ cup fresh lime juice (calamansi or Persian limes)
1.Put the egg yolks into a medium size bowl and beat with a hand-held electric mixer on medium- to medium-high speed until the yolks are thickened and paler in color. This step gives the filling its super smooth texture. (Note: A few years ago I developed a key lime pie recipe for a food magazine and found that actually beating the egg yolks for a few minutes gave the pie a welcome lightness).
2. Gradually mix in the sweetened condensed milk on low speed or stir it in with a spoon. A tablespoon or two at a time, stir in the lime juice. Stir the filling a few times with a rubber spatula to make sure it’s completely smooth. And that’s it! At this point many recipes say to pour the filling into the crust and refrigerate. I like to bake the filling a short time to ensure a lovely smooth texture.
To Bake:
Preheat the oven to 350˚F with a rack in the middle position. Put your baked pie crust onto a baking sheet and scrape the filling into the crust.
Put the pie in the oven and set a square of aluminum foil over the top of the pie. The foil will rest on the edges of the crust above the filling.
Bake 15 minutes. Remove the foil and the pie from the oven and set the pie on a cooling rack. When completely cool, refrigerate the pie, uncovered, for 5 to 6 hours or overnight.
Whipped Cream Topping
1 ½ cups heavy cream or whipping cream
2 tablespoons confectioners’ sugar
1 teaspoon vanilla
Make sure your beaters and bowl are cold. Put them in the fridge and hour or so beforehand. Pour the cream into the chilled bowl and add the sugar and vanilla. Beat until the cream holds a firm shape. Spread over the filling and smooth the top. Cut into servings with a sharp knife.
If you like, place a few raspberries and/or blueberries alongside the wedge of pie.
The pie holds up really well in the fridge for up to four days.
Makes 8 servings.
Have fun with this pie!
Looks and sounds yummy! Hope you are still enjoying Hawaii! Snow squall currently in the Helena, MT area.
Wonderful Greg! I must try the calamansi lime in my KLP. I actually prefer the Persian to Key, if I may be so bold. I use a little lemon juice in mine and fold whipped cream into the filling. And my crust is roasted pecan and graham crackers. I just posted my recipe yesterday in my SS post. Thanks for sharing with us! 😊