Key Lime Bars Graham Crust

My sister-in-law brought these to a July 4th party years ago and I literally chased her around the kitchen for the recipe. The way that tart lime cuts through the sweet condensed milk is just perfect for summer weather when you want dessert but not something heavy.

I made these for my book club last month and served them still slightly chilled from the fridge. Three different people asked for the recipe before they even finished their first bar. There is something about key limes specifically that hits different than regular limes, more floral somehow.

Ingredients

• Graham Cracker Crumbs: Fresh crumbs work best here, pulse whole crackers in a food processor or put them in a ziplock and crush with a rolling pin
• Granulated Sugar: The sugar in the crust helps it hold together and gives a slight crisp edge
• Unsalted Butter: Must be melted so it coats every crumb evenly, let it cool slightly before mixing
• Egg Yolks: Room temperature yolks incorporate more smoothly into the condensed milk
• Sweetened Condensed Milk: Do not use evaporated milk, the thick sweetness is what creates the silky texture
• Key Lime Juice: Fresh is amazing but Nellie and Joes bottled juice works perfectly fine in a pinch
• Key Lime Zest: Use a micrograter if you have one to avoid the bitter white pith
• Salt: Just a pinch balances all the sugar and makes the lime flavor pop

Instructions

Preheat your oven:

Get it to 350°F and line your 8x8 pan with parchment, letting some hang over the sides like little handles

Make the crust:

Mix the crumbs, sugar, and melted butter until it feels like wet sand then press it firmly into the pan using the bottom of a measuring cup

Bake the crust:

Let it go for about 10 minutes until you can smell the graham crackers getting toasty

Whisk the filling:

Beat those yolks until they are thick and pale, then add everything else and whisk until smooth

Fill and bake again:

Pour the lime mixture over the warm crust and bake until the center is set but still jiggles slightly when you shake the pan

The hard part:

Let them cool completely then chill for at least 2 hours before cutting into squares

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My daughter now requests these for every birthday instead of cake. We started making little flags with toothpicks and washi tape for each bar, which makes them feel extra special for serving.

Making Them Ahead

These bars are actually better the next day when all the flavors have had time to become best friends with each other. I wrap the pan tightly with plastic and they last happily in the fridge for up to four days.

The Crust Situation

Pressing the crust firmly into the pan is crucial, I learned this the hard way when my first batch fell apart. Use the flat bottom of a measuring cup or glass to really pack it down tight before baking.

Serving Suggestions

A dollop of lightly sweetened whipped cream on top makes these feel restaurant worthy. I also love adding a thin slice of key lime as garnish because the green looks so pretty against the pale yellow filling.

• Cold plates work best for serving so the bars hold their shape
• Let them sit out for about 10 minutes before eating for the ideal texture
• A sprinkle of sea salt on top takes them to the next level

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There is something so satisfying about a recipe that looks impressive but comes together so easily. These bars have become my go-to for whenever I need to bring dessert somewhere, and they never fail to make people happy.

Common Recipe Questions

→ How do I achieve the perfect creamy texture?

Use fresh key lime juice and gently whisk the filling ingredients until smooth. Avoid overbaking to keep a slightly soft center.

→ Can I substitute graham cracker crust?

Yes, gluten-free graham cracker crumbs work well for those avoiding gluten, maintaining that buttery, crunchy base.

→ What is the ideal chilling time?

Chilling for at least 2 hours allows the filling to fully set and flavors to meld, though 3–4 hours is optimal.

→ How can I enhance the lime flavor?

Adding fresh lime zest on top or mixing it into the filling intensifies the citrus aroma and tang.

→ Is it possible to prepare these bars in advance?

Yes, they can be made a day ahead and stored covered in the refrigerator without compromising taste or texture.

→ Can the filling texture be adjusted?

To vary firmness, slightly alter baking time: less for creamier, more for firmer texture, but avoid overbaking.