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Key Lime Pie Bars Recipe
This Key Lime Pie Bars Recipe gives you everything you love about classic key lime pie—creamy, tangy filling and buttery graham cracker crust—baked into easy, shareable bars that are perfect for parties, potlucks, and summer dessert tables.
These key lime dessert bars are bright, refreshing, and surprisingly simple, with a smooth, citrusy filling that sets up beautifully in the oven and slices into neat little squares. If you love tropical dessert bars with a bit of zing, you’re in exactly the right place.
What Makes This Key Lime Pie Bars Recipe So Special?
I’ve been baking for my family and friends for over 30 years, and these baked key lime bars are one of those recipes that never comes home from a party in the same pan. Every square disappears. Quickly.
This Key Lime Pie Bars Recipe takes the iconic flavors of a traditional key lime recipe—tart, fragrant limes, creamy filling, and that golden graham cracker crust—and turns it into a pan of easy lime dessert bars you can slice, pack, and serve without fuss. No pie plates, no worrying about cracked tops, and much easier to cut for a crowd.
I especially love making these in late spring and summer. The bright citrus flavor cuts through all the heavy cookout food and feels like a breath of Florida sunshine. But honestly, I make them in the middle of January too, when I’m tired of beige food and want something cheerful and tangy.
From a “healthy-ish” angle, they’re lighter than many rich cakes or frostings:
- The lime juice provides natural brightness, so you don’t need piles of extra sugar.
- The filling uses sweetened condensed milk, which gives body and sweetness in one ingredient.
- You can use reduced-fat condensed milk and low-fat sour cream or Greek yogurt and still get a lovely creamy lime filling.
And you know what? These graham cracker crust bars are very forgiving. You don’t need pastry skills. If you can stir, press, and whisk, you can make beautiful, impressive key lime squares.
Why You’ll Love This Key Lime Pie Bars Recipe
- Bright, tangy flavor: These tangy key lime bars are perfectly balanced—sweet, tart, and refreshing without being puckery.
- Easy to transport: Bars are sturdier than pie; they pack up beautifully for potlucks, picnics, and party dessert bars.
- Simple ingredients: Everything is easy to find at a regular grocery store—no specialty baking aisle trip needed.
- Beginner-friendly: No pastry dough, no water bath, no fancy tools; just a bowl, whisk, and baking pan.
- Make-ahead friendly: These citrus dessert bars taste even better the next day after a good chill.
- Customizable: You can add coconut, a pretzel crust, or tweak the sweetness to your taste with simple swaps.
- Neat, clean slices: The baked key lime bars set up firmly, so you get tidy key lime squares instead of a runny mess.
- Perfect for warm weather: Summer dessert bars that hold up well at cookouts and pool parties (as long as you keep them cool).
- Great for small or large groups: Cut the pan into 9 big bars or up to 24 smaller key lime dessert bites.
Ingredients for the Best Key Lime Pie Bars
Let’s walk through what you’ll need to make this lime pie bar recipe and how to choose the best ingredients. Using real citrus and the right crust makes all the difference.
For the graham cracker crust:
- 1 ½ cups (about 12 full sheets) graham cracker crumbs
Use classic honey graham crackers. You can pulse them in a food processor or crush them in a zip-top bag with a rolling pin. - ¼ cup granulated sugar
Helps the crust hold together and adds a light sweetness. - ½ teaspoon fine sea salt
Balances the sweetness; don’t skip this, even in desserts. - 7 tablespoons unsalted butter, melted
You want it fully melted so every crumb gets coated. Salted butter works too—just reduce the added salt slightly.
For the creamy lime filling:
- 4 large egg yolks, room temperature
Yolks add richness and help the lime custard bars set properly. - 1 can (14 ounces) sweetened condensed milk
This is the backbone of that classic, silky key lime texture. Don’t use evaporated milk; it’s not the same. - ½ cup sour cream or full-fat Greek yogurt
Adds body and a slight tang. Greek yogurt is a great swap if that’s what you keep on hand. - ½ cup fresh key lime juice (or regular lime juice)
Fresh is best for that bright, floral note. If you use bottled key lime juice, choose a good-quality brand like Nellie & Joe’s. - 1–2 teaspoons finely grated lime zest
From key limes or regular limes. Zest adds a deeper citrus flavor without extra acidity. - 1 teaspoon pure vanilla extract
Rounding out the citrus so it doesn’t taste harsh. - Pinch of salt
Again, salt makes the flavors pop.
For serving (optional but lovely):
- Whipped cream or whipped topping
- Extra lime zest or thin lime slices for garnish
- Toasted coconut flakes (optional, for a tropical dessert bars twist)
A quick note from my kitchen: If you’re using key limes, they’re tiny—about the size of a large marble. You’ll need quite a few to get ½ cup juice (usually 15–20 key limes). Regular Persian limes work just fine, and I use them often when I don’t feel like juicing a mountain of tiny limes.
How to Make Key Lime Pie Bars (Step-by-Step)
This Key Lime Pie Bars Recipe comes together in three simple stages: crust, filling, and bake. Take your time with each step, and you’ll be rewarded with creamy, dreamy squares of lime goodness.
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Preheat and prep the pan.
Preheat your oven to 350°F (175°C). Line an 8×8-inch or 9×9-inch baking pan with parchment paper, leaving some overhang on two sides so you can lift the bars out later. Lightly spray the parchment and sides with nonstick spray. This makes cutting much easier. -
Make the graham cracker crust.
In a medium bowl, combine graham cracker crumbs, sugar, and salt. Stir with a fork until mixed, then pour in the melted butter. Mix until all the crumbs look like damp sand and no dry spots remain. If you squeeze a handful and it holds together, you’re good. -
Press and pre-bake the crust.
Pour the crumb mixture into your prepared pan. Use your fingers or the bottom of a measuring cup to press the crumbs firmly and evenly across the bottom. Press a little up the sides if you’d like a slight edge. Bake for 8–10 minutes, until fragrant and lightly golden. Set aside to cool for a few minutes while you make the filling. -
Whisk the egg yolks.
In a large mixing bowl, whisk the egg yolks for about 1 minute until they’re slightly thickened and a bit lighter in color. You don’t need an electric mixer, but you can use one on low speed if your arm gets tired. -
Add the sweetened condensed milk.
Pour in the sweetened condensed milk and whisk until the mixture is smooth and fully blended—about 1–2 minutes. This step gives you that luscious, custardy base for the creamy lime filling. -
Stir in sour cream, vanilla, and salt.
Add the sour cream (or Greek yogurt), vanilla, and a small pinch of salt. Whisk until the mixture is silky and no streaks remain. It should look pale yellow and very smooth. -
Add lime juice and zest.
Slowly whisk in the lime juice and zest. At first, the mixture may look a little thinner, but as it sits for a minute or two, it will thicken slightly. The acid in the lime juice starts reacting with the milk—this is what helps these lime custard bars set so nicely. Let the filling rest for about 5 minutes. -
Pour the filling over the crust.
Give the filling mixture one last stir, then pour it over the warm (but not piping hot) graham cracker crust. Tilt the pan gently or use an offset spatula to spread it into an even layer. Tap the pan once or twice on the counter to pop any big air bubbles. -
Bake until just set.
Bake at 350°F (175°C) for 15–18 minutes. The edges should look slightly set, and the center should still have a tiny bit of jiggle when you nudge the pan—like firm Jell-O, not liquid. Don’t overbake; overbaking can cause cracks and a rubbery texture instead of that smooth, creamy lime filling. -
Cool, then chill thoroughly.
Remove the pan from the oven and cool at room temperature for about 30–45 minutes. Then cover and chill in the refrigerator for at least 3 hours, or overnight. This firming time is what turns these into cleanly sliced key lime dessert bars instead of a soft pudding. -
Slice and garnish.
Use the parchment overhang to lift the chilled slab out of the pan and place it on a cutting board. Use a long, sharp knife, wiping the blade between cuts, to slice into 9 large bars or up to 16–20 smaller party dessert bars. Top with whipped cream, a sprinkle of lime zest, and maybe a few toasted coconut flakes if you’re feeling extra tropical.
Servings & Timing
- Yield: About 9–16 bars, depending on how you slice them
- Prep Time: 20 minutes
- Bake Time: 25–28 minutes total (crust + filling)
- Chill Time: At least 3 hours (overnight is best)
- Total Time: About 4 hours, mostly hands-off
If you’re planning these summer dessert bars for a gathering, I suggest baking them the day before and chilling overnight. It makes party day a lot calmer—you can just slice and serve.
Tasty Variations on Classic Key Lime Pie Bars
Once you’ve made the basic Key Lime Pie Bars Recipe, it’s fun to play a little. Here are some simple twists:
- Coconut Key Lime Bars: Stir ½ cup sweetened shredded coconut into the crust or sprinkle on top before baking for a tropical dessert bars vibe.
- Pretzel Crust Lime Bars: Swap half the graham cracker crumbs for crushed pretzels for a salty-sweet crunch.
- Gluten-Free Lime Pie Bar Recipe: Use gluten-free graham-style crackers or gluten-free cookie crumbs; the rest of the recipe stays the same.
- Extra Tangy Key Lime Bars: Add an extra tablespoon of lime zest and reduce the sugar in the crust slightly if you want even more zing.
- Margarita-Inspired Lime Bars (Adults Only): Add 1–2 tablespoons tequila and 1 teaspoon triple sec to the filling, and sprinkle flaky salt over the crust before baking.
- Lighter Lime Bars: Use reduced-fat sweetened condensed milk and low-fat Greek yogurt; the texture will be slightly softer but still very tasty.
How to Store, Freeze, and Make Ahead
One of the best things about these citrus dessert bars is how well they keep. They’re actually better after they’ve had time to rest.
Storing in the refrigerator:
- Store leftover bars in an airtight container in the fridge for up to 4–5 days.
- If stacking, place parchment or wax paper between layers so they don’t stick.
Freezing key lime squares:
- Chill the bars completely, then cut into squares.
- Place the bars on a baking sheet in a single layer and freeze until solid (about 1–2 hours).
- Transfer to a freezer-safe container or zip-top bag with parchment between layers.
- Freeze for up to 2 months.
Thawing:
- Thaw frozen bars in the refrigerator overnight.
- For a quicker option, let them sit at room temperature for about 30 minutes, but they’re best cold.
Make-ahead tips:
- You can prepare the crust and bake it a day ahead; just wrap the pan tightly and keep at room temperature.
- You can also make the filling, cover it, and refrigerate for up to 24 hours before baking. Whisk it briefly before pouring over the crust.
- For parties, I like to bake and chill them the day before, then garnish with whipped cream and lime zest just before serving so everything looks fresh.
Personal Notes & Helpful Tips
After making some version of these lime bars for years, I’ve picked up a few small tricks that make a big difference in how they turn out.
- Use fresh juice if you can. Bottled key lime juice is handy and works, but fresh lime juice gives you a cleaner, brighter flavor. Even a mix of fresh lime and a little bottled key lime juice can be lovely.
- Don’t rush the chill time. The filling needs time to fully set. Cutting them too soon will give you messy edges and a softer texture. Still delicious, just not as pretty.
- Room temperature yolks blend better. If your eggs are cold, set them in a bowl of warm (not hot) water for 5–10 minutes. This helps the filling come together more smoothly.
- Adjust sweetness to taste. If you like your tangy key lime bars really tart, use a little less sugar in the crust and keep the zest on the higher side.
- Slice with a hot knife. Run your knife under hot water, wipe it dry, then cut. Clean and repeat between slices. You’ll get those sharp bakery-style edges that make people think you bought them.
- Use a metal pan if possible. Glass pans work, but a light-colored metal pan usually bakes more evenly. If using glass, you may need an extra minute or two in the oven.
And just a little real-life note: I once brought a tray of these key lime dessert bars to a summer block party and watched the “serious chocolate people” go back for second and third helpings. Citrus can win over even the brownie crowd.
Key Lime Pie Bars Recipe FAQs
Can I use regular limes instead of key limes?
Yes. Regular Persian limes work perfectly in this Key Lime Pie Bars Recipe; the flavor is a bit less floral but still bright and delicious.
Can I make this recipe in a 9×13 pan?
You can, but you’ll want to increase the recipe by about 1.5 times and watch the bake time—start checking the filling around 18–20 minutes.
Why did my key lime dessert bars crack on top?
Usually, this means they were slightly overbaked. Aim for a tiny jiggle in the center and let them finish setting in the fridge.
Can I make these lime bars without eggs?
This version relies on egg yolks for structure. For an egg-free version, you’d need a different style of filling, more like a no-bake key lime dessert, which changes the recipe quite a bit.
Is it safe to eat the egg yolks in these bars?
Yes. The bars are baked, and the yolks cook through during baking, just like in a custard pie.
Can I cut back the sugar in the recipe?
You can slightly reduce the sugar in the crust without problems. The sweetness in the filling comes from sweetened condensed milk, which you can’t reduce without changing the texture.
Do these need to be refrigerated?
Absolutely. Because of the eggs and dairy, these lime custard bars should be kept chilled until serving and then returned to the fridge within about 2 hours.
How long can I leave them out at a party?
Try to limit room-temperature time to 1½–2 hours. For summer parties, I like to serve them on a tray set over a shallow pan of ice packs to keep them cool.
Final Thoughts: Bring a Little Sunshine to Your Table
These Key Lime Pie Bars are everything I love in a dessert bar recipe—simple to make, easy to share, and full of bright, tangy flavor that wakes up your taste buds. The creamy lime filling, buttery graham cracker crust, and cheerful citrus aroma make them a little slice of sunshine any time of year.
If you try this Key Lime Pie Bars Recipe, I’d love to hear how it went—tell me in the comments how you served them, if you tried any fun twists, or which crowd you shared them with. And if you enjoy these, you might also like exploring my other citrus and summer dessert bars; once you start down the lime-and-lemon path, it’s hard to stop.
Key Lime Pie Bars
Ingredients
- 1 1/2 cups graham cracker crumbs about 12 full sheets, crushed
- 1/4 cup granulated sugar
- 1/2 teaspoon fine sea salt
- 7 tablespoons unsalted butter melted
- 4 large egg yolks room temperature
- 14 ounces sweetened condensed milk 1 can; do not substitute evaporated milk
- 1/2 cup sour cream or full-fat Greek yogurt
- 1/2 cup fresh key lime juice or regular lime juice
- 1 teaspoon lime zest up to 2 teaspoons, finely grated
- 1 teaspoon pure vanilla extract
- salt pinch, for filling
- whipped cream or whipped topping for serving, optional
- extra lime zest or thin lime slices for garnish, optional
- toasted coconut flakes optional, for garnish
Instructions
- Preheat your oven to 350°F (175°C). Line an 8x8-inch or 9x9-inch baking pan with parchment paper, leaving some overhang on two sides to lift the bars out later. Lightly spray the parchment and sides with nonstick spray.
- In a medium bowl, combine the graham cracker crumbs, granulated sugar, and fine sea salt. Stir with a fork until evenly mixed, then pour in the melted butter. Mix until all the crumbs look like damp sand and no dry spots remain.1 1/2 cups graham cracker crumbs, 1/4 cup granulated sugar, 1/2 teaspoon fine sea salt, 7 tablespoons unsalted butter
- Pour the crumb mixture into the prepared pan. Use your fingers or the bottom of a measuring cup to press the crumbs firmly and evenly across the bottom, pressing slightly up the sides if desired. Bake for 8–10 minutes, until fragrant and lightly golden. Set aside to cool for a few minutes while you make the filling.
- In a large mixing bowl, whisk the egg yolks for about 1 minute until slightly thickened and a bit lighter in color. You can do this by hand or with an electric mixer on low speed.4 large egg yolks
- Pour in the sweetened condensed milk and whisk until the mixture is smooth and fully combined, about 1–2 minutes, creating a custardy base.14 ounces sweetened condensed milk
- Add the sour cream (or Greek yogurt), vanilla extract, and a pinch of salt. Whisk until the mixture is silky and no streaks remain. It should be pale yellow and very smooth.1/2 cup sour cream, 1 teaspoon pure vanilla extract, salt
- Slowly whisk in the lime juice and lime zest. The mixture may look a bit thinner at first, but it will thicken slightly as it sits. Let the filling rest for about 5 minutes so the acid can react with the milk and start to set.1/2 cup fresh key lime juice, 1 teaspoon lime zest
- Give the filling a final stir, then pour it over the warm (not piping hot) graham cracker crust. Tilt the pan gently or use an offset spatula to spread it into an even layer. Tap the pan once or twice on the counter to release any large air bubbles.
- Bake at 350°F (175°C) for 15–18 minutes. The edges should look slightly set and the center should still have a tiny jiggle when you nudge the pan, like firm gelatin rather than liquid. Do not overbake, or the bars may crack and become rubbery.
- Remove the pan from the oven and cool at room temperature for about 30–45 minutes. Then cover and chill in the refrigerator for at least 3 hours, or overnight, until fully set.
- Use the parchment overhang to lift the chilled slab out of the pan and place it on a cutting board. With a long, sharp knife, slice into 9 large bars or up to 16–20 smaller bars, wiping the blade between cuts for clean edges. Top with whipped cream, extra lime zest, thin lime slices, and/or toasted coconut flakes if desired.whipped cream or whipped topping, extra lime zest or thin lime slices, toasted coconut flakes
