These key lime pie bars have a buttery graham cracker crust and a tangy filling made with just egg yolks, sweetened condensed milk, key lime juice and zest. Topped with homemade whipped cream and key lime slices, it's a super refreshing summer treat! It's like my classic key lime pie, just in bar form!
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What are Key Limes?
Key limes are the smaller, sweeter cousin to regular limes. They're also known as the Mexican Lime or the West Indies Lime. They have a unique floral flavor that's tart without being too acidic.
In the US, key limes are in season from June to August so you can usually only find them at the grocery store during those months, which is why these key lime pie bars are such a popular summer treat!
However, if you aren't lucky enough to find fresh key limes at the store, bottled key lime juice works great! Nellie & Joe's key lime juice is delicious and is sold at most grocery stores as well as amazon.
If you like key lime as much as I do, you might also like these key lime pie macarons or these key lime pie cupcakes!!
Ingredient Notes
You only need a few ingredients to make these key lime pie bars!
Graham Cracker Crust - For the simple graham cracker crust, you just need graham crackers, sugar, and melted butter!
Sweetened Condensed Milk - The sweetened condensed milk helps sweeten and thicken the filling. You can find it in the baking aisle at your local grocery store.
Egg Yolks - The egg yolks help the filling set when baked. You can use the leftover egg whites to make macarons or meringues!
Key Lime Juice and Zest - The stars of the show! I always prefer baking with fresh key limes, but if you can't find them you can use bottled key lime juice and the zest from regular limes.
The complete list of ingredients and amounts is located in the recipe card below.
This bar is the perfect combination of sweet & tart- the best!!
- Ashley 
How to Make Key Lime Pie Bars
Preheat oven to 325°F.
Add the graham crackers to the food processor and pulse until you have small, even crumbs.
In a medium bowl, combine the graham cracker crumbs, sugar, and melted butter and mix with a fork until all the crumbs are fully coated with butter.
Press the mixture evenly along the bottom of an 8x8 inch square pan and pack tightly by pressing down with the back of a measuring cup (you can also use a 9x9 inch pan, the bars will just be a little thinner).
Bake for 15 minutes at 325°F and then let cool on a wire rack for at least 15 minutes before filling.
While the crust is cooling, make the filling! In a large bowl, whisk together the egg yolks and lime zest. Then add in the sweetened condensed milk and key lime juice and whisk until fully combined and smooth.
Pour the filling into the slightly cooled crust and bake at 325°F for 15-18 minutes or until the center is set but still jiggles slightly.
Remove from the oven and let cool on a wire rack at room temperature until cool, then transfer to the fridge and let chill for a minimum of 3 hours but ideally overnight.
I like to top these key lime pie bars with my favorite homemade whipped cream! You can pipe a dollop in the center of each bar, or just smooth an even layer of whipped cream on top! Then just garnish with sliced key limes and more key lime zest!
Recipe FAQ's
These key lime pie bars will keep covered in the fridge for up to 3 days.
You can, but I don't recommend it. Key limes have a different, sweeter flavor than regular limes which is what makes key lime pie so good! But you can find bottled key lime juice in most grocery stores and online!
Key lime bars will be runny if the filling hasn't fully set. Make sure you let it chill in the fridge for at least 3 hours before slicing into it, but overnight is best!
To get clean slices of these key lime bars, run a super sharp knife under hot water until the blade is warm, then wipe it dry. Then cut a single slice and repeat. It's a bit tedious to clean the knife before every cut, but you get perfect slices every time!
To make a larger batch of these key lime pie bars, simple double the recipe and use a 9x13 inch pan instead.
Tips for Success!
For best results I always recommend using weight measurements (especially when baking) because it's the most accurate. Kitchen scales are super affordable and also reduce the number of dishes you have to do! However, all my recipes also include US customary measurements for convince. Use this chart to convert measurements for common ingredients!
Substitutions: In all my recipes, I've included substitutions that I know will work, but I cannot guarantee results if you substitute ingredients that I have not recommended. [For example, granulated sugar and honey are indeed both sweeteners but they have very different properties so they can not always be swapped 1:1. Using honey in a cookie recipe that calls for granulated sugar will yield a giant mess.] In the recipe card you'll find links to the specific ingredients/brands that I use.
A note on salt: I almost exclusively use Diamond Crystal Kosher Salt because it's the best all-purpose salt for cooking and baking. If you're not using kosher salt, consult this handy guide for a conversion chart! When in doubt, if you're using table salt just reduce the amount by half for baked goods. When cooking, I prefer to under-salt because you can always add more! If you've over-salted, adding a little bit of acid (like lemon juice) can help.
More Recipes You Might Like!
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Recipe Card
Key Lime Pie Bars
Special Equipment
Ingredients
Graham Cracker Crust
- 1 ½ cups graham cracker crumbs
- ¼ cup granulated sugar
- 6 tablespoons unsalted butter, melted
Key Lime Filling
- 4 large egg yolks
- 1 tablespoon key lime zest
- 14 ounces sweetened condensed milk
- ½ cup key lime juice
Top With
- homemade whipped cream
- key lime slices
- key lime zest
Instructions
- Preheat oven to 325°F.
- Add the graham crackers to the food processor and pulse until you have small, even crumbs.
- In a medium bowl, combine the graham cracker crumbs, sugar, and melted butter and mix with a fork until all the crumbs are fully coated with butter.
- Press the mixture evenly along the bottom of an 8x8 inch square pan and pack tightly by pressing down with the back of a measuring cup (you can also use a 9x9 inch pan, the bars will just be a little thinner).
- Bake for 15 minutes at 325°F and then let cool on a wire rack for at least 15 minutes before filling.
- While the crust is cooling, make the filling! In a large bowl, whisk together the egg yolks and lime zest. Then add in the sweetened condensed milk and key lime juice and whisk until fully combined and smooth.
- Pour the filling into the slightly cooled crust and bake at 325°F for 15-18 minutes or until the center is set but still jiggles slightly.
- Remove from the oven and let cool on a wire rack at room temperature until cool, then transfer to the fridge and let chill for a minimum of 3 hours but ideally overnight.
- I like to top these key lime pie bars with my favorite homemade whipped cream! You can pipe a dollop in the center of each bar, or just smooth an even layer of whipped cream on top! Then just garnish with sliced key limes and more key lime zest!
Notes
Nutrition
The nutritional information on this website is only an estimate and is provided for convenience and as a courtesy only. The accuracy of the nutritional information for any recipe on this site is not guaranteed.
Ashley Johnson says
This bar is the perfect combination of sweet & tart- the best!!