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Our Key Lime Pie Bars are a heavenly combination of sweet and tart. With a buttery cookie crust and delectable key lime pie filling, these are the best key lime bars ever! Plus, they take no more than 30 minutes to prep and bake before cooling in the fridge.
Top them off with powdered sugar and take a bite. We promise these will be your new favorite spring and summer dessert recipe!
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🍽 Equipment
If you have ever taken a bite of key lime pie and wished you could make it at home, but thought it would be too hard to do, this is the recipe for you!
Rest assured that the process for making homemade key lime pie is easier than it seems. In fact, this recipe is so easy, a total beginner can make it without any trouble.
Key lime pie, like cheesecake, is a matter of making the crust and filling, baking, and then letting it cool. They are so similar that key lime cheesecake is a popular choice for cheesecake flavor!
Unlike cheesecake recipes, however, key lime bars require less time to chill and are much more forgiving than your average cheesecake filling. You won’t have to worry about the filling cracking!
To get started, you will need:
- Your oven
- A 9 by 9-inch baking pan
- Aluminum foil
- Non-stick cooking spray
- A hand mixer or stand mixer
- Knife to cut the pie into bars
- A food processor or rolling pin to crush the cookies (you can also just use your hands!)
The steps for making this key lime pie recipe is as simple as making the crust, mixing the filling, and then combining the two in a greased, foil-lined baking pan to bake.
Preparing the key lime pie squares, including the baking time, only takes about 30 minutes, and then you’re done to let them cool off for a couple of hours in the fridge!
🍋 Ingredients
Key lime pie crust ingredients:
- 14-16 graham cracker cookies (equal to 2 cups when finely crushed)
- 5-6 Tablespoons salted butter, melted
You can buy a box of graham cracker cookie crumbs from the store, or crush your own cookies.
In total, whether you’re using homemade crumbs or boxed, you will need 2 cups of crumbs. This is equal to about 14-16 cookies.
For additional flavor, you can add in vanilla cookies, too! Try crushing vanilla sandwich cookies, like we do for our Strawberry Shortcake Ice Cream Cake, or vanilla wafers, as in our Carlota de Limón.
Key lime pie filling ingredients:
- 4 ounces cream cheese, room temperature (about half of your typical container of cream cheese)
- 4 egg yolks from 4 large eggs*
- 1 14 ounce can sweetened condensed milk (not fat free!)
- ½ cup key lime juice (from fresh key limes or bottled key lime juice)
- 2 teaspoons lime zest from 1 lime – learn how to zest a lime
- Powdered sugar (optional, but so tasty)
For the key lime pie filling, you can juice your own key limes or use bottled key lime juice. If you’re making your own, you will need around 4 key limes for ½ cup of juice.
If you have access to key limes, I recommend giving fresh limes a try! These little limes are wonderfully tart. Just make sure they are the right limes! Regular limes also work, but won’t have quite the same flavor.
However, using bottled key lime juice works perfectly and tastes great, too. You can find key lime juice in the juice aisle at your grocery store, usually near lemon juice and lemonade. If not, try the baking aisle or even produce.
What should I do with my leftover egg whites?
There is no need to throw out the egg whites. Make our Mini Pavlova Recipe! It calls for exactly 4 egg whites and is a delicious little dessert everyone loves.
Or, make Egg White Bites for breakfast the next day. Perfect!
🔪 Instructions
- Preheat your oven to 350°F. Line a 9×9″ baking pan with aluminum foil. Use enough so that it hangs over the sides just slightly. Lightly spray the inside of the pan with non-stick cooking spray and set aside.
- Crush 14-16 graham crackers into fine crumbs using a food processor or a bag and rolling pin, enough to make 2 cups of crumbs. You can also use boxed crumbs.
- Pour the crushed cookie crumbs into a mixing bowl with 5-6 tablespoons of melted butter (5 will yield a slightly more crumbly crust). Mix together until fully combined, then add the crust to the prepared baking pan.
Press the crust down until it forms a nice, tight layer at the bottom of the pan. Bake for 10 minutes in your preheated oven while you make the key lime pie filling. - In a large mixing bowl, beat 4 ounces cream cheese on high speed until smooth using a hand mixer or stand mixer.
Beat in 4 egg yolks and scrape down the sides as necessary.
Finally, beat in 1 14 ounce can of sweetened condensed milk, ½ cup key lime juice, and 2 teaspoons lime zest. Mix until smooth. - Pour the completed key lime pie filling over the crust in the pan.
Bake for about 15 minutes or until the edges of the bars begin to brown. If they haven’t yet, leave them in for another 2-3 minutes. - Allow the key lime pie to cool at room temperature, in the pan, on a rack. A wire rack works best for cooling. Once it cools off, add the pie to the refrigerator and let it chill for 2 hours.
- After at least 2 hours, remove the key lime pie from the refrigerator and lift it out of the pan using the aluminum foil. Cut into approximately 16 bars (see my tips below for cutting the bars!). Top with powdered sugar if you like, serve, and enjoy!
⭐ Family Foodie Tips
- Don’t skip out on adding the aluminum foil. It really makes it so easy to lift the bars out of the baking dish after they’re done chilling!
- Cutting the pie. To easily cut the pie into 16 key lime bars, cut the pie in half both ways so you have 4 even, large squares. Then, cut those 4 squares in half both ways to make a total of 16 smaller bars.
My #1 tip is that if you love this recipe, you need to try our Milk Bar Pie Squares and Almond Ooey Gooey Butter Cake Bars. These recipes are out-of-this-world delicious and easy, too!
👪 Serving Size
This recipe for key lime pie bars will make a total of 16 palm-sized bars. They are perfect for a party like a backyard BBQ or potluck!
Everyone who tries one of these delicious key lime bars will ask you for the recipe, I guarantee it. They are that good! And the best part is, they are so easy to make.
💭 Frequently Asked Questions
What is a key lime?
Key limes are a hybrid citrus that are much smaller than your average lime, with a different flavor. The name “Key” lime comes from the Florida Keys, where the fruit originates!
Key limes are ideal for making key lime pie, of course, and are also popular to use in cocktail recipes.
In fact, a little key lime in our Frozen Strawberry Daiquiri Recipe would be a great way to use any leftover juice you might have!
What is the difference between a lime and a key lime?
The typical lime you buy from the grocery store is a Persian lime. The difference between Persian limes and key limes is in the size and flavor of the limes.
Key limes are very unique. They’re tart like limes, but with a more sweet-and-sour balance, and are less acidic than regular limes. Key limes also have more seeds than regular limes, are much smaller, and tend to have a more yellow rind.
Can you substitute limes for key limes?
Yes! You can use regular limes in most key lime recipes, but the flavor will not be quite the same.
Some people do like the taste of regular limes in a key lime pie, so if you enjoy the tart flavor, go ahead and give them a try.
Of course, I recommend using key limes if you’re able to. Look for the limes themselves or the bottled key lime juice. Either will work!
How do you know when key lime pie is done?
In the case of these key lime pie bars, the edges of the bars will begin to brown. The center of a good key lime pie will have a slight jiggle to it in the center (like a cheesecake!) but will still be firm.
How long will key lime pie keep?
Cover your key lime pie bars with plastic wrap in a pan or keep them in an air-tight container, in the refrigerator, for up to 3 days.
Can you freeze key lime pie?
Yes! The easiest way to do this is to follow all of the steps for making the key lime pie, but stop before you cut it into bars.
Place the whole pie onto a baking sheet and add it to the freezer for 2-3 hours or until frozen solid.
Once it’s frozen, remove it from the freezer and wrap it completely and tightly in plastic wrap. Layer it a few times with the wrap for best results.
If you have a 9×9″ foil pan to store and wrap it in, that’s even better!
When ready to enjoy, let the pie thaw in the refrigerator overnight. Cut into squares and dig in!
🍰 Serving Suggestions
- Top key lime pie bars off with a little whipped cream in addition to the powdered sugar. It is delicious.
- Try serving these as a dessert alongside your favorite summer grilling recipes and side dishes for BBQ.
- Try it with the strawberry lime topping from our Carlota de Limón. This combination is unbelievable!
📖 Similar Recipes
Love dessert recipes like these key lime pie squares? Then I guarantee you will love…
- Instant Pot Cheesecake
- Strawberry Swirl Cheesecake
- Strawberry Dole Whip
- Homemade Strawberry Shortcake Biscuits
- Double Chocolate Brownie in a Mug
Did you try this key lime pie recipe? Let me know in the comments below what you think, and please leave a rating! We love to hear from you.
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Key Lime Pie Bars
Ingredients
Key lime pie crust ingredients:
- 14-16 graham cracker cookies equal to 2 cups when finely crushed
- 5-6 Tablespoons salted butter melted
Key lime pie filling ingredients:
- 4 ounces cream cheese room temperature, about half of your typical container of cream cheese
- 4 egg yolks from 4 large eggs
- 14 ounce can sweetened condensed milk not fat free!
- ½ cup key lime juice from fresh limes or bottled
- 2 teaspoons lime zest from 1 lime
- Powdered sugar optional
Instructions
- Preheat your oven to 350°F. Line a 9×9″ baking pan with aluminum foil. Use enough so that it hangs over the sides just slightly. Lightly spray the inside of the pan with non-stick cooking spray and set aside.
- Crush 14-16 graham crackers into fine crumbs using a food processor or a bag and rolling pin, enough to make 2 cups of crumbs. You can also use boxed crumbs.
- Pour the crushed cookie crumbs into a mixing bowl with 5-6 tablespoons of melted butter (5 will yield a slightly more crumbly crust). Mix together until fully combined, then add the crust to the prepared baking pan.Press the crust down until it forms a nice, tight layer at the bottom of the pan. Bake for 10 minutes in your preheated oven while you make the key lime pie filling.
- In a large mixing bowl, beat 4 ounces cream cheese on high speed until smooth using a hand mixer or stand mixer. Beat in 4 egg yolks and scrape down the sides as necessary. Finally, beat in 1 14 ounce can of sweetened condensed milk, ½ cup key lime juice, and 2 teaspoons lime zest. Mix until smooth.
- Pour the completed key lime pie filling over the crust in the pan. Bake for about 15 minutes or until the edges of the bars begin to brown. If they haven’t yet, leave them in for another 2-3 minutes.
- Allow the key lime pie to cool at room temperature, in the pan, on a rack. A wire rack works best for cooling. Once it cools off, add the pie to the refrigerator and let it chill for 2 hours.
- After at least 2 hours, remove the key lime pie from the refrigerator and lift it out of the pan using the aluminum foil. Cut into approximately 16 bars (see my tips below for cutting the bars!). Top with powdered sugar if you like, serve, and enjoy!
Notes
- Don’t skip out on adding the aluminum foil. It really makes it so easy to lift the bars out of the baking dish after they’re done chilling!
- Cutting the pie. To easily cut the pie into 16 key lime bars, cut the pie in half both ways so you have 4 even, large squares. Then, cut those 4 squares in half both ways to make a total of 16 smaller bars.
- Use your leftover egg whites to make Starbucks Egg Bites or Mini Pavlovas!
Ellen Folkman says
These squares look delicious! I love anything Key lime.
Mary Ellen says
I made these today. Next time I will do a 9×13 pan and double the filling. Otherwise they are really good!
Marion Myers says
So happy to hear you enjoyed them Mary Ellen 🙂 They do disappear quickly, so doubling the filling is a great idea! Thanks for stopping by! Have a great week!
LORI WILLIAMS says
did you try the fat free sweetened condensed milk and the recipe didn’t work? I’d like to try, just wondering
Em Beitel says
Hi Lori! Thank you for your question! You could absolutely use fat-free sweetened condensed milk for the recipe if you like. The two have similar consistencies and should yield a similar result. However, we added the note as using fat-free may change the consistency just slightly in the end product. More fat usually gives a creamier consistency. If you try fat-free sweetened condensed milk, we would love to know how it works for you!