Last Updated on July 9, 2025 by Jennifer Osborn
Key Lime Bars are sweet, tangy, and ridiculously quick and easy to make in just 20 minutes. With a buttery graham cracker crust and creamy lime filling, they’re perfect for summer parties, potlucks, celebrations or anytime you crave citrusy dessert magic.
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Okay so I'll spill the secret right now, a bit of fresh lime zest and juice makes these lime bars extra tangy.
No need to use a key lime for this tiny addition, I use a regular Eureka lime from the grocery store.
I don't add much, just a teaspoon of zest and a teaspoon of juice.
Nellie & Joe's, which you can find with the mixers in most grocery store liquor aisles, is reliably delicious and tart but adding a bit of fresh takes the tang up a level.
Love key lime? Then you must also try Nellie & Joe's Key Lime Pie and No-bake Key Lime Pie and Key Lime Pie Dip.
Ingredients
Filling
- Egg yolks
- Sweetened condensed milk
- Nellie and Joe's Key Lime Juice (can swap ½ cup fresh lime juice)
- Fresh limes
Graham cracker crust
- graham cracker crumbs
- granulated sugar
- pinch of cinnamon (optional)
- melted butter
How to Make Key Lime Pie Bars
Make the Crust and Bake It
If you need detailed crust instructions, see my full 8x8 Graham Cracker Crust Recipe.
Make the Filling and Pour It Over the Crust
Pro Tip: Add Freshly Grated Lime Zest to Filling
Bake the Bars
Recipe Notes
Chilling the bars makes slicing them much easier and neater. An hour in the fridge or 30 minutes in the freezer should be perfect.
You can use the zest and juice of a regular Eureka or other grocery store lime in addition to the Nellie and Joe's to flavor your bars, no need to hunt down a key lime.
Sweetened condensed milk gives structure to these bars.
This sweet, thick milk is also an essential ingredient in lemon bars with graham cracker crust recipe and the salty sweet crunchy bars.
Whipped cream, especially homemade whipped cream, is the perfect topping. You could also top your dessert bars with Mascarpone Cream.
More posts you might find helpful: Does lime juice go bad?, How to use up a bottle of Nellie & Joe's And a recipe for a great warm weather drink with lime juice.
Storage and Make Ahead Instructions
Make Key Lime Pie Bars up to three days in advance.
Or you can make the filling in advance, put it in a plastic container with a tight fitting lid and store in the refrigerator until you're ready to bake the bars but no longer than 3 days.
You can make the graham cracker crust in advance two to three days in ahead too. Just bake, let cool, then cover and leave at room temperature.
To serve, fill the crust, bake it, then chill and slice.
Freeze key lime pie bars, wrapped in plastic wrap or wax paper, then tucked into a freezer safe container, for up to two months.
Some professionals say lime custard bars will last up to three months in the freezer but I think they start to lose their quality.
Score the bars using a bench scraper before slicing. You can use a ruler as a guide. Score three horizontal lines and then four vertical lines.
Since these are easy bars to slice into, you can just use a metal bench scraper and skip the knife.
Frequently Asked Questions
Can I use regular limes?
Yes, while key limes are traditional, regular limes (like Persian or Eureka limes) work perfectly in this recipe. The addition of fresh zest and juice gives plenty of tart flavor, even without true key limes.
Do I need bottled juice?
I recommend bottled Nellie & Joe's Key Lime Juice — it’s convenient, easy to find, and has that perfect tart flavor. That said, you can make this recipe by juicing regular limes you’ll find at the grocery store year-round.
Can I make these ahead?
Definitely. You can make Key Lime Pie Bars up to 3 days in advance. Chill them in the fridge, covered, and slice while still cold for the cleanest cuts.
Can I freeze key lime bars?
Yes! Key Lime Bars freeze perfectly. Wrap twice and freeze for up to 2 months. Wrap them tightly in plastic wrap and store in an airtight freezer container. Thaw in the fridge before serving. For best texture, I don’t recommend freezing longer than 2 months.
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Recipe
Key Lime Pie Bars
Key lime pie bars with a buttery graham cracker crust and tangy lime filling. A creamy, easy-to-slice dessert perfect for citrus lovers.
Ingredients
- 1.-¼ cups graham cracker crumbs ( approximately 10 full sheets of graham crackers if you're crushing your own) or a third of a box
- 5 Tablespoons melted butter
- ¼ cup granulated sugar
- ½ teaspoon ground cinnamon (optional for crust)
- 3 egg yolks
- ½ cup key lime juice (Nellie & Joe's)
- 1 14-ounce can sweetened, condensed milk]
- 1 grocery store lime (for 1 teaspoon zest and 1 teaspoon juice)
- Whipped cream (optional)
Instructions
Prepare an 8x8 pan and line with parchment paper. Use binder clips to hold the parchment paper to the pan. (optional)
Prepare the crust: stir graham cracker crumbs, granulated sugar, ground cinnamon (optional) and melted butter in a medium or large mixing bowl. Pour crumbs into pan. Use the bottom of a flat water glass or measuring cup to press crumbs into pan. Bake at 350°F for 7 to 10 minutes. Let cool.
While crust is baking, prepare the filling.
Use a rasp grater to zest one lime over a piece of wax paper or parchment to capture all the zest.
Slice lime in half and sqeeze one half over a small bowl to capture juice.
Beat egg yolks, key lime juice, teaspoon of zest and teaspoon of fresh juice and sweetened, condensed milk into a large mixing bowl. (you can use the bowl you made the crust in) until well-combined. Mixture will begin to thicken.
Pour into cooled graham crust amd bake at 350F° for 15 minutes.
Key Lime Bar filling will have turned from an off-white cream color to yellow when done baking.
It wiill laso smell delicious and citrusy when.done.
Let come to room temperature for at least 30 minutes then wrap and chill in the refigerator or freezer to chill.
Chilled bars will be easier to neatly slice.
Top with whipped cream just before serving.
Notes
Be sure to use sweetened, condensed milk--not evaporated milk. Your recipe will flop if you get these two ingredients mixed up.
Nutrition Information
Yield 12 Serving Size 1Amount Per Serving Calories 198Total Fat 9gSaturated Fat 4gTrans Fat 0gUnsaturated Fat 4gCholesterol 59mgSodium 169mgCarbohydrates 28gFiber 1gSugar 11gProtein 3g
Nutrition information is an estimate as I am not a registered dietician.
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