Name: Grandma's Lemon Bars
Prep time: 25 min
Cook time: 55 min
Total time: 85 min
Ingredients: 2 1/2 cups all-purpose flour; 5/8 cup confectioners' sugar; 1 1/4 cup unsalted butter (room temperature and cubed); 4 large eggs; 2 cups granulated sugar; 1/4 cup all-purpose flour; 1 teaspoon baking powder; 6 Tablespoons fresh lemon juice; 2 Tablespoons confectioners' sugar

These are my grandma's beloved lemon bars that my family has been baking for generations! This easy, old-fashioned recipe for classic lemon bars with a buttery shortbread crust and tangy lemon filling requires less than 30 minutes of hands-on time and makes a 9x13 pan of the best homemade lemon bars.

Angled view of a lemon bar with a bite missing.

If you invite me to a summer BBQ, there's a good chance I'm bringing a pan of these lemon bars. After all, they are one of my all-time favorite desserts!

This is my grandma's lemon bar recipe - the one my family has been making for generations - and I get asked for the recipe every time I bring them to a party. The recipe makes enough to feed a crowd and is the perfect blend of rich, buttery shortbread with sweet-tart lemon custard (topped with a dusting of confectioners' sugar, of course!), so it's no surprise that everyone wants the recipe!

And okay, yes, I'll admit I did tweak Grandma's recipe slightly, increasing the amount of crust because I like a nice, substantial crust to hold up the zesty lemon filling in my lemon bars.

Overhead view of a lemon bar with a small lemon slice on parchment paper.

Best of all, these lemon bars are incredibly simple to make. They start with a 3-ingredient shortbread crust that's par-baked (aka partially baked) before the filling is added to ensure a nice, crisp shortbread.

The lemon custard filling is also super easy! Simply whisk together 5 ingredients, pour the filling over the parbaked crust, and pop the whole thing back in the oven. Once they've cooled, sprinkle the bars with confectioners' sugar and enjoy!

Even though these lemon squares are easy to make, I've included a few tips below to help ensure that yours are absolutely perfect!

Ingredient Notes & Substitutions

See recipe card at the bottom of this post for full ingredient list and measurements.

Recipe ingredients with labels on a white background.

Confectioners' Sugar - Since confectioners' sugar is a fine powder, it helps to create a shortbread with no grittiness from sugar granules. It also adds a beautiful powder layer on top of the bars.

Unsalted Butter - Butter is key to the shortbread crust, giving it flavor and holding it together as it bakes. I use unsalted butter here, but you could use salted if you prefer a bit of salt in your bars.

Lemon Juice - For the best flavor, I recommend using fresh lemon juice for these bars.

Eggs - Eggs (along with a bit of flour) thicken the lemon custard filling.

Baking Powder - Baking powder adds a tiny bit of lift in the filling, keeping it from being too dense.

Special Equipment

In addition to essential baking equipment (like a mixing bowl and whisk), you'll need a pastry cutter for cutting the flour into the dry ingredient mixture.

A sifter or fine mesh sieve is also helpful for sprinkling the confectioners' sugar on top of the bars.

Step-By-Step Recipe Instructions

See recipe card at the bottom of this post for detailed recipe instructions.

Shortbread dough in a glass mixing bowl with a pastry cutter.

Step 1: Make the shortbread crust. Whisk together flour and confectioners' sugar. Cut the butter into the flour mixture until a slightly crumbly dough forms.

Step 2: Spread the dough into a 9x13 pan and gently press the dough to create a solid crust.

Step 3: Bake the crust at 350°F for 20-25 minutes, just until golden. Let cool slightly while you make the filling.

Lemon filling in a batter bowl with a whisk.

Step 4: Make the lemon filling. Beat eggs, sugar, flour, baking powder, and lemon juice until smooth and slightly thickened.

Lemon custard poured over shortbread crust in a 9x13 pan.

Step 5: Pour the lemon mixture over the still-warm crust.

Step 6: Bake the lemon bars at 300°F for 30 minutes.

Lemon bars sprinkled with powdered sugar in a 9x13 pan.

Step 7: Once the bars are completely cooled, sprinkle with confectioners' sugar and slice into squares.

Allison's Top Tips

Don't skip spraying the parchment paper. The butter in the crust will keep the bottom of the lemon bars from sticking, but the lemon custard will stick to the parchment paper if it's not sprayed.

The easiest way to evenly sprinkle the confectioners' sugar over the bars is to use a sifter or fine mesh sieve. Place the sugar into a sifter or sieve and to hold it 6 inches above the bars while moving it around the surface of the bars, gently tapping it with your hand.

The key to perfect lemon bars is baking them for the correct amount of time. To check the bars, give the pan a little wiggle in the oven. If the filling jiggles, it needs more time. The filling should just reach the point where it no longer jiggles.

Angled view of lemon bars with lemon slices scattered on parchment paper.

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