Key Lime Pie Bars

Key Lime Bars — There’s plenty of bold lime flavor in these easy bars that are a twist on the classic pie everyone loves! This is the perfect make-ahead dessert for potlucks and parties! 

Easy Key Lime Dessert

I’ve been blogging for 5 years and can count on one hand the number of lime recipes I have. And that includes squirting some lime over avocado. Time to branch out and make a classic.

Except rather than making classic key lime pie, I made key lime pie bars. I’ll always take bars over pie since making pie crust is never on my to-do list, and this is a one bowl, no-mixer recipe.

Just like my Lemon Bars, there’s nothing lackluster about how much robust lime flavor is present. The filling is tart and bold without being overpowering. While baking, the butter and brown sugar in the crust caramelize, and it plays perfectly off the lime.

It’s the same crust I used in Peanut Butter Swirled Cheesecake BarsSalted Caramel Apple Cheesecake Bars, and Salted Caramel Pumpkin Cheesecake Bars. It seriously makes the bars. It’s a keeper, even for someone who doesn’t like crust. It’s got just enough crispiness and crunch, yet there’s slight chewiness, and it holds together without crumbling, something that graham cracker crusts don’t always do.

For the filling, I used actual key limes. They’re smaller ping-pong sized limes, about half the size of average limes. They’re typically grown in the Florida Keys, hence the name. I found a bag of about 25 for $2.49 at my regular grocery store and literally needed almost all of them to get 1/2 cup lime juice.

The filling is simply lime juice, sweetened condensed milk, 1 egg, sour cream (I used lite), and sugar. Because I didn’t want the bars to resemble cheesecake, I avoided using any cream cheese and instead used sour cream to lend richness and creaminess.

After whisking together the filling and tasting it, I thought it was a little bitter. Taste your mixture, and because all limes and palettes vary, add sugar if necessary.

After removing the pan from the oven, the bars looked like a beating heart was pulsing under the surface for over 2 minutes. It was like watching on a science experiment on the cooling rack. It should go without saying, but you must allow them to cool for at least a couple hours at room temp, cover them, and refrigerate until chilled. I cannot imagine eating warm Key lime pie.

 It’s an easy key lime dessert to make a few days before an event and just keep parked in the fridge until you need it. The bars remind me of warm weather, ocean breezes, and I want to blast some Margaritaville.

And make one, too. To wash down the bars with.

What’s in Key Lime Bars? 

To make these key lime pie bars, you’ll need:

  • Unsalted butter
  • Graham cracker crumbs
  • Light brown sugar
  • Cornstarch
  • Salt
  • Sweetened condensed milk
  • Egg
  • Lime juice
  • Sour cream
  • Granulated sugar

How to Make Key Lime Pie Bars

Whisk together the graham cracker crust mixture, then firmly press into the bottom of a foil-lined 8×8-inch baking pan. Bake the crust for 10 minutes. 

Meanwhile, whisk together the key lime pie filling. Once the crust has been in the oven for 10 minutes, pour the filling into the pan and continue baking until the center is set with only some slight jiggle.

Don’t let the key lime bars get ‘browned’, they should stay fairly pale and light.

Can I Double This Recipe? 

You most likely can double the ingredients and bake these key lime pie bars in a 9×13-inch pan. However, I haven’t tried this myself so I can’t say for sure if the bake time would be altered. 

Can I Use Regular Limes? 

If you can’t find Key limes, just use regular limes or I’m sure bottled lime juice will be just fine. I’m wishing I had gone either of those routes because juicing all of those mini limes wasn’t what I had bargained for.

Tips for Making Key Lime Bars

Note that the ingredients list calls for sweetened condensed milk and NOT evaporated milk. They’re two totally different milk products, so read the labels closely before purchasing. 

You can purchase pre-made graham cracker crumbs or you can make your own by pulsing regular graham crackers in a food processor until sandy in texture. 

Baking times will vary based on oven and climate variance, the type of sour cream used (lite makes batter runnier thus taking longer to bake), and if sugar was added (makes batter runnier). The center should be set and not too jiggly. Always watch your bars, and not the clock. Bake until done.

Yield: 9

Key Lime Pie Bars

Prep Time 15 minutes
Cook Time 55 minutes
Chill Time 2 hours
Total Time 3 hours 10 minutes

There's plenty of bold lime flavor in these easy bars that are a twist on the classic pie everyone loves! The perfect make-ahead dessert for potlucks! 



  • 1/2 cup unsalted butter, melted
  • 1 cup graham cracker crumbs
  • 3/4 cup light brown sugar, packed
  • 1 tablespoon cornstarch
  • pinch salt, optional and to taste


  • one 14-ounce can sweetened condensed milk
  • 1 large egg
  • 1/2 cup lime juice (freshly squeezed Key lime juice is optimal; use regular limes if necessary, or substitute with bottled lime juice only if you must)
  • 1/2 cup sour cream (lite is okay)
  • up to 1/2 cup granulated sugar, optional and if necessary, see directions
  • thinly sliced limes for garnishing, optional


    1. Preheat over to 350F. Line an 8×8-inch pan with aluminum foil, spray with cooking spray; set aside.

    Make the Crust:

    1. In a large microwave-safe bowl, melt the butter, about 1 minute on high power.
    2. Add all remaining crust ingredients and mix with a fork to combine.
    3. Turn loose crumbs out into prepared pan and using a spatula, pack mixture firmly into pan in an even, smooth, flat layer.
    4. Bake for 10 minutes. While crust bakes, prepare the filling.

    Make the Filling:

    1. Combine first 4 ingredients in a large mixing bowl (same one used for crust is fine), and whisk until smooth and combined.
    2. Taste filling. If it’s bitter or too tart, add sugar as necessary, to taste. I used 1/2 cup sugar because my Key limes were a bit bitter.
    3. After 10 minutes, remove crust from oven and pour filling over it, smoothing the top lightly with a spatula.
    4. Return pan to oven and bake for about 45 minutes, or until center is set with only some slight jiggle; some looseness is okay, but there should not be sloshing in the center. You’ll notice the filling near the edges start setting up first; remove pan from oven when center starts to take on the same appearance as the edges. Don’t let the bars get ‘browned’, they should stay fairly pale and light. Bars firm up more as they cool. Bars will be bubbling vigorously so use caution when removing them from the oven.
    5. Allow bars to cool in pan on a wire rack for about 2 hours.
    6. Cover pan with foil (to prevent fridge smells), and refrigerate for at least 2 hours, or overnight, or until well chilled before slicing and serving.
    7. Optionally, garnish with thinly sliced limes before serving.


  • Bars will keep airtight in the refrigerator for up to 1 week.

Nutrition Information:



Serving Size:


Amount Per Serving: Calories: 464Total Fat: 19gSaturated Fat: 11gTrans Fat: 0gUnsaturated Fat: 7gCholesterol: 76mgSodium: 151mgCarbohydrates: 69gFiber: 1gSugar: 61gProtein: 7g

More Easy Bar Desserts: 

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Blueberry Pie Bars— These pie bars are one of my all-time favorite frozen blueberry recipes! They have the flavors you love in a blueberry pie, but you don’t have to mess around with homemade pie crust.

Mississippi Mud Pie Bars – An EASY, almost no-bake dessert with a chocolate chip cookie base, chocolate pudding, sweetened cream cheese, Oreos, and hot fudge!! RICH, decadent, indulgent, and a great party dessert that you can MAKE-AHEAD!!

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Banana Cream Pie Bars – Faster and easier than making a banana cream pie and taste AMAZING!! A crunchy crust, tender banana slices, luscious banana pudding, and creamy whipped topping make these layered pie bars WINNERS!!

Glazed Cherry Pie Bars — The cherry bars are like cherry pie but easier. There’s a buttery, soft, tender crust topped with cherry pie filling before being baked and glazed.

Salted Caramel Maple Pecan Pie Bars— This pecan pie bars recipe is a fast, one-bowl, no-mixer recipe, but the bars taste like you slaved over them. So much easier than making pecan pie!