Key Lime Pie Bars

Introduction

Key Lime Pie Bars capture all the bright, tangy flavor of the classic pie in a portable, crowd-pleasing bar form. You get a buttery graham cracker crust, a creamy and intensely citrus filling, and a fluffy toasted meringue topping. It’s the perfect dessert for bringing to gatherings or enjoying a special treat at home.

Prep & Cook Time

Prep Time: 45 minutes

Cook Time: 45 minutes

Total Time: 1 hour 30 minutes

Servings: 16 bars

Ingredients

• 1¾ cup graham cracker crumbs
• ¼ cup granulated sugar
• 6 Tablespoons salted butter (melted)
• 10 large egg yolks
• 2½ cups sweetened condensed milk
• 1¼ cups key lime juice
• 2 teaspoons lime zest
• 3 large egg whites (room temperature)
• 1 cup granulated sugar
• ¼ cup water

Instructions

1. Preheat your oven to 350°F (175°C). Line a 9×13 inch baking pan with parchment paper, leaving an overhang on two sides for easy removal.
2. Make the crust: In a medium bowl, stir together the graham cracker crumbs and ¼ cup granulated sugar. Pour in the melted salted butter and mix until the crumbs are evenly coated and resemble wet sand.
3. Press the crumb mixture firmly and evenly into the bottom of the prepared pan. Bake for 10 minutes. Remove from the oven and let it cool slightly while you prepare the filling. Reduce oven temperature to 325°F (160°C).
4. Make the filling: In a large bowl, whisk the 10 egg yolks until smooth. Whisk in the sweetened condensed milk until fully combined. Slowly whisk in the key lime juice and lime zest until the mixture is smooth and has thickened slightly.
5. Pour the filling over the warm crust. Bake at 325°F for 20-25 minutes, or until the edges are set but the center still has a slight jiggle. Remove from the oven and let cool completely at room temperature, then refrigerate for at least 4 hours or overnight.
6. Make the meringue topping: In the bowl of a stand mixer fitted with the whisk attachment (or using a hand mixer), beat the 3 room temperature egg whites on medium-high speed until soft peaks form.
7. While the egg whites are beating, combine 1 cup granulated sugar and ¼ cup water in a small saucepan. Cook over medium heat, without stirring, until the syrup reaches 240°F (soft-ball stage) on a candy thermometer.
8. With the mixer running on medium speed, carefully and slowly pour the hot sugar syrup in a thin stream down the side of the bowl into the whipped egg whites. Avoid hitting the whisk. Once all syrup is added, increase speed to high and whip until the meringue is glossy, stiff, and cool to the touch, about 5-7 minutes.
9. Spread or pipe the meringue over the completely chilled filling. Use a kitchen torch to toast the meringue until golden brown in spots. Slice into 16 bars and serve.

Variations

• No-Torch Meringue: Instead of torching, dollop the meringue onto the filling and place the entire pan under the oven broiler for 1-2 minutes, watching closely, to brown.
• Swirled Topping: For a simpler look, gently spread the meringue and use the back of a spoon to create decorative swirls before toasting.
• Mini Bars: Use a 9×9 inch pan for a thicker bar, adjusting the baking time for the filling by adding 5-10 minutes.
• Crustless Serving: For a gluten-free option, simply scoop the chilled filling and meringue into serving glasses, layering it with crumbled graham cracker crust on top.

Tips for Success

• Ensure your egg whites are at room temperature for the meringue; they will whip to a greater volume.
• For the cleanest slices, dip your knife in hot water and wipe it clean between each cut.
• Use bottled key lime juice for consistent, potent flavor, but fresh regular lime juice can be substituted in a pinch.

Storage & Reheating

Store bars in an airtight container in the refrigerator for up to 3 days. The meringue may begin to weep or soften over time. These bars are best served cold and are not suitable for reheating.

FAQ

Can I use regular lime juice instead of key lime juice?

Yes, you can. The flavor will be slightly different but still delicious. Use the same volume (1¼ cups) of fresh regular lime juice.

Why do I need to use a candy thermometer for the meringue?

The hot sugar syrup cooks the egg whites, making the meringue stable and safe to eat. The precise temperature (240°F) ensures the syrup is the right consistency to create stiff, glossy peaks.

Can I make these without the meringue topping?

Absolutely. The bars are complete with just the crust and filling. You can top them with a dollop of whipped cream instead.

My filling didn’t seem to set firmly after baking. Is it done?

Yes, it’s likely done. The filling sets further as it cools and chills. It should be jiggly but not liquid when you remove it from the oven.

What can I do with the leftover egg whites?

The recipe uses 3 for the meringue. You can use any extra whites to make meringue cookies, an egg white omelet, or add them to a morning scramble.

Can I freeze Key Lime Pie Bars?

It’s not recommended to freeze the bars with the meringue topping, as it will become grainy. You can freeze the bars (without topping) for up to a month. Thaw in the refrigerator and add fresh meringue before serving.