Heavenly Key Lime Pie

Refreshingly cool and silky, Key lime pie is welcome on all summer picnic tables—and all holiday tables, dinner tables, or birthday tables, for that matter.

The combination of Key lime juice, zest, condensed milk, and egg yolks yields a pie filling that is rich and tart without being cloyingly sweet. The perfect crust companion—graham cracker crust—lends sweetness and a bit of nutty flavor, but it really is a vessel to hold the unforgettable filling.

We call this Key lime pie recipe heavenly because it's precisely where you'll think you've been transported after one bite. We've perfected this recipe over decades of making Key lime-flavored recipes, so we've really got the balance of the sweet-tart Key lime juice and the sweetened condensed milk just right.

Here, learn how to make key lime pie step by step. Plus, find out where this favorite citrus pie really originated.

Where Did Key Lime Pie Originate?

You're thinking Florida, right? There's hardly a restaurant menu in the Sunshine State without this dessert.

Turns out, the origins of the Key lime pie are a little murky. Some Florida historians believe the pie was invented in the Florida Keys in the late 1800s, but what can be proven is another story: A researcher found that the pie likely originated with a condensed milk manufacturer in New York City—except it was a lemon and condensed milk pie in this earliest iteration. Then, savvy Florida bakers swapped lemons for local Key limes, and Florida's favorite pie was born.

Still, if you're transported to a tiny island with a tropical drink in hand after one bite, you're not alone. Let them fight over the origins. We'll have another slice of pie, please.

Key Lime Pie Ingredients

This Key lime pie really is simple. We've kept the ingredient list short and sweet so it's ultimately an easy key lime pie. Here, the things you'll need to gather to make this pie:

• A graham cracker crust: We prefer a homemade one if you have the time, but a store-bought shortcut is always appreciated.
• Sweetened condensed milk: This ingredient creates the base of the rich, luscious pie filling. It's sweet and creamy, which is precisely what this pie needs.
• Key lime juice and zest: Key limes can be hard to find when they're not in season (which is June through September in Florida but year-round in other places). But bottled Key lime juice is usually always available.
• Egg yolks: This helps set the filling so it doesn't run when you slice into the pie.
• Whipped cream: Here's another place where we think homemade is so much better that we encourage you to do it if you have time (it's part of the recipe below). But store-bought whipped topping is also acceptable in a pinch.

How To Make Key Lime Pie

Step 1: Make the filling. Once you have your crust prepared, it's time to make the filling, which includes the sweetened condensed milk, lime juice, lime zest, and egg yolks. Pour the filling into the graham cracker crust.

Step 2: Bake the pie. Even though this pie is ultimately served chilled, you need to bake the pie to set the filling. This takes about 15 minutes. Then, let the pie cool for an hour before putting it in the refrigerator to chill for an hour.

Step 3: Top with whipped cream. Get out your stand mixer or hand mixer, and whip up the cream and powdered sugar. Dollop it onto the chilled pie, and add Key lime slices for garnish if you want.

How To Store Key Lime Pie

The pie needs to be served chilled, so keep it in the fridge until you're ready to slice and serve. Whipped cream will hold for a while, but if you're making this pie ahead of time, wait to whip the cream and top the pie until you're ready to present it.

Have leftovers? Cover the pie plate in plastic wrap, and keep it in the fridge up to 3 days.

Can you freeze Key lime pie?

Yes, you can freeze Key lime pie. But if you're planning to do that, bake it in a foil pan instead of your glass or metal one. And don't add the whipped cream. It won't make it through the freeze and thaw cycles.

Once baked, let the freezer-bound pie cool completely. Wrap the entire pan in plastic wrap, then aluminum foil. Label the pie with the food's name and the date you're putting it in the freezer. It can stay in the freezer up to 3 months.

When you're ready to enjoy it, take the pie out of the freezer, and let it thaw overnight in the fridge. Make the whipped cream topping just before serving.

Frequently Asked Questions

Can you use "regular" limes instead of Key limes?

Yes, you can use Persian limes in place of Key limes in Key lime pie.

Persian limes, the kind you are most likely to find at the grocery store, are plentiful and easier to find than Key limes if you live outside Florida.

However, the flavor of a Key lime pie made with Persian limes may not be the same experience as you remember from the slice you had while visiting the Florida Keys: Persian limes are more tart and lack the floral aroma of Key limes. They'll still make a perfectly delicious lime pie. It just might be a bit different than what you're expecting.

What is special about Key lime pie?

Key limes are tiny, about half the size of Persian limes. It takes a baker a lot of work to get enough juice for a Key lime pie. All that work and love means the Key lime pie is a special treat, one to be treasured when you get a slice.

Also, the flavor of a Key lime is more floral and sweeter than regular limes, which makes for a pie that is more refreshing and unique.

What is Key lime pie so popular in Florida?

Key limes only grow in subtropical environments like Southeast Asia—and the Florida Keys! While most Key limes sold in the U.S. today are grown in Mexico or Central America, it's still a prized crop to the growers in Florida who dedicate part of the grove to the petite citrus fruit.

Editorial contributions by Kimberly Holland.