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If you crave the sharp, citrusy punch of key lime pie but don’t feel like wrangling crusts and pastry pans, these key lime pie bars are an easy way out. They’ve got the same creamy filling, buttery base, and refreshing tang, only in neat little squares you can lift out of the pan without ceremony. I think of them as the friendly, low-maintenance cousin of the classic pie perfect for a summer BBQ, or honestly, whenever you want something bright and not too fussy. The crust holds together well, yet it still melts in your mouth, and the lime zing is strong but balanced. Oh, and one small thing I swear by: zest your limes right before juicing. The oils fade fast, and fresh zest makes a noticeable difference in fragrance. So, should we start baking?

Why This Recipe Works Every Time

What’s happening here isn’t magic exactly, but a very reliable bit of kitchen chemistry. Lime juice, being highly acidic, doesn’t just add flavor it actually thickens the filling by curdling the proteins in the sweetened condensed milk. No need for gelatin or cornstarch. Egg yolks come in to reinforce the structure and bring that custardy richness most of us expect.

As for the crust: yes, it gives crunch, but it also acts like insulation. Instead of the filling boiling or curdling, it bakes gently until set. I tinkered with the crust-to-filling ratio quite a bit (three rounds of testing, to be exact) before settling on this version. Too much crust felt dry, while too little made the bars taste like citrus pudding on a cracker. Here, you get just enough of both in every bite.

A Few Kitchen Notes For You

• Lime juice really does the heavy lifting. If you’ve ever wondered why old-fashioned key lime pie doesn’t call for stabilizers, this is why.
• Egg yolks aren’t just for richness they emulsify the whole mix, so you get a smooth, silky custard that doesn’t break apart when sliced.
• And if you’ve ever pressed crumbs into a pan and had them fall apart later, melted butter is the fix. It coats each crumb, helping the crust bake into a sturdy but tender layer.

Ingredients (metric first)

For the crust

• Graham crackers or digestive biscuits — 200 g (about 2 cups crumbs)
• Unsalted butter, melted — 100 g (7 tbsp)
• Granulated sugar — 40 g (3 tbsp)
• Pinch of sea salt

For the filling

• Sweetened condensed milk — 400 g (14 oz can)
• Egg yolks — 4 large (~80 g)
• Fresh lime juice — 120 g (½ cup)
• Finely grated lime zest — 2 tsp

Optional topping

• Whipped cream — 120 g (½ cup)
• Extra lime zest — for garnish

Equipment

• 8-inch (20 cm) square pan (a lined pan makes life easier)
• Mixing bowls, whisk, spatula
• Digital scale (helpful but not mandatory)

Nice extras: offset spatula for spreading, microplane for zest, and parchment overhang to lift out the bars cleanly.

Step-by-Step (with cues)

Prep pan and oven
Heat oven to 175°C (350°F). Line your pan with parchment, leaving “handles” that help you pull out the bars later.

Make the crust (10 minutes)
Mix crumbs, sugar, salt, and melted butter until it resembles damp sand. Press firmly—really firmly—into the pan using a glass.
Cue: It should look compact and faintly shiny.
Bake 8–10 minutes, until just golden. Cool.

Filling (5–7 minutes)
Whisk egg yolks until pale, about 1–2 minutes by hand. Slowly add condensed milk. Once smooth, whisk in lime juice and zest last.
Cue: The mixture will thicken slightly and coat the back of a spoon.

Bake (18–22 minutes)
Pour over crust, smooth the top, and bake until edges are set but the center jiggles softly—think Jell-O wobble. Don’t let it brown.
Cue: Internal temp should be 74–76°C (165–170°F).

Chill (3–4 hours)
Cool at room temp, then refrigerate until fully chilled.

Slice and serve
Lift the parchment, slice with a hot knife, and wipe between cuts. Add whipped cream or fresh zest if desired.

Troubleshooting

• Bars collapsed in center → Filling overmixed or overbaked. Go gentler next time.
• Watery filling → Either skipped the bake or used bottled juice. (Trust me, bottled juice won’t set properly.)
• Crumbly crust → Not enough butter, or it wasn’t pressed firmly.
• Too tart → You probably used juice from oversized limes. Measure precisely.
• Rubbery texture → Straight-up overbaking. Stop at the jiggle stage.

Substitutions & Variations

• Egg-free: Swap yolks for 200 g thick Greek yogurt. Texture softer but still sliceable.
• Dairy-free: Use coconut condensed milk + vegan butter—flavor leans tropical.
• Gluten-free: Use GF biscuits or nut-based crumbs.
• Flavor twist: Add lemon zest, or swirl in raspberry jam before baking.

Scaling and Storage

• 9×13 pan: Scale recipe up by 1.5×.
• Mini muffin version: Bake crust 6 min, filling 10–12.
• Keeps: 5 days in fridge, 2 months frozen. (Skip freezing with whipped cream, it ruins texture.)

Serving Ideas

Lovely with a dollop of whipped cream and berries. For fun, drizzle a little chocolate sauce—it’s unexpectedly good with lime.

Notes from My Kitchen

Batch 1 (bottled juice): flat, blah flavor. Never again.
Batch 2 (whole eggs): filling turned rubbery. Yolks only is the way.
Batch 3: upped butter in crust, finally got that perfect slice.
Batch 4: egg-free test with yogurt—surprisingly decent texture.

Final take: fresh juice + 4 yolks + 100 g butter crust = reliable, balanced bars that last nearly a week in the fridge.

Nutrition (per bar, 1 of 16)

210 kcal, 11 g fat, 24 g carbs, 4 g protein (estimates only).

Refreshingly Tangy Key Lime Bars

Course: DessertCuisine: AmericanDifficulty: Intermediate

Servings

16

servings

Prep time

20

minutes

Cooking time

25

minutes

Calories

210

kcal

Total time

4

hours 

30

minutes

Chill Time: 3–4 hours

Creamy, tangy, and perfectly sliceable, these key lime pie bars deliver all the flavor of a traditional pie in easy-to-share squares. With a crisp biscuit crust, silky citrus filling, and optional whipped cream topping, they’re refreshing, reliable, and beginner-friendly.

Ingredients

For the crust

• Graham crackers or digestive biscuits — 200 g (about 2 cups crumbs)

• Unsalted butter, melted — 100 g (7 tbsp)

• Granulated sugar — 40 g (3 tbsp)

• Pinch of sea salt

• For the filling

• Sweetened condensed milk — 400 g (1 can / 14 oz)

• Egg yolks — 4 large (about 80 g)

• Fresh lime juice (key lime or Persian lime) — 120 g (½ cup)

• Finely grated lime zest — 2 tsp

• For topping (optional)

• Whipped cream — 120 g (½ cup)

• Extra lime zest for garnish

Directions

• Preheat oven
  Preheat to 175°C (350°F), middle rack. Line 8-inch pan with parchment, leaving overhang for lifting bars later.
• Make crust (10 minutes)
  Combine biscuit crumbs, sugar, salt, and melted butter.
  Mix until texture resembles wet sand.
  Press firmly into pan using a glass bottom until smooth and compact.
  Visual cue: Surface should look even and slightly glossy.
  Bake 8–10 minutes until lightly golden. Cool 5 minutes.
• Prepare filling (5–7 minutes)
  Whisk egg yolks until pale and slightly thickened (1–2 min).
  Slowly whisk in condensed milk until smooth.
  Add lime juice and zest, whisk just until combined.
  Visual cue: Mixture should coat the back of a spoon and pour in light ribbons.
• Bake filling (18–22 minutes)
  Pour filling into crust, smooth top.
  Bake until edges set and center jiggles like soft jelly. Do not brown.
  Doneness: Internal temp 74–76°C (165–170°F).
• Chill (3–4 hours)
  Cool to room temp, then refrigerate covered for at least 3 hours.
• Slice & garnish
  Lift bars using parchment, cut with a hot knife (wipe between slices).
  Top with whipped cream and zest if desired.

Notes

• Storage
  Counter: Up to 4 hours.
  Fridge: Airtight up to 5 days.
  Freezer: Wrap tightly up to 2 months. Thaw overnight in fridge. Do not freeze with topping.
• Notes & Tips
  Fresh lime juice is essential—bottled lacks flavor.
  Crust crumbling? Add 10–15 g more butter.
  For egg-free: Replace yolks with 200 g Greek yogurt. Texture slightly softer.
  For dairy-free: Use coconut condensed milk + vegan butter.
  For gluten-free: Use GF biscuits.
  Pro Tip: Always zest limes right before juicing to capture maximum fragrance.