Gluten Free Lemon Bars

These gluten free lemon bars have a crisp, buttery shortbread crust and a smooth, bright lemon custard filling that sets just right every time. They’re simple to make, slice neatly, and deliver that classic balance of sweet and tart without any guesswork.

Why this recipe works

The texture is exactly what you want from classic lemon bars, and is even better without gluten. The crust bakes up tender but sturdy, with just enough chew to hold its shape under the filling without turning soft or greasy.

The filling is smooth, creamy, and full of real lemon flavor. Fresh lemon zest flavors the crust, not just the custard, so every bite tastes balanced and bright instead of flat or overly sweet.

The filling sets properly because you’re not guessing when it’s done. Since ovens vary, I give you multiple doneness cues so you can use your best judgment and pull it at just the right moment. That’s how you avoid a filling that’s underbaked or firm and rubbery.

Recipe ingredients

Here's a bit about the ingredients you'll need to make these bars, how to select the best of each, and what they do to contribute to the best result:

• Gluten free flour blend: Both the shortbread-style crust and the filling require a gluten free flour blend with superfinely ground rice flour as a base, without any xanthan gum. I’ve found that adding a binder like that makes the crust more chewy and the filling gummy, not smooth. The flour blend adds structure to both components of the bars. You can use my 3-ingredient blend or Nicole's Best. If you choose to use King Arthur Flour's gf blend without xanthan gum, I highly recommend sifting it multiple times before you measure to ensure there's no grittiness.
• Confectioners' sugar: In the crust, it adds sweetness and helps create a lightly crispy crumb that melts in your mouth. We dust more on top for extra sweetness and because it looks pretty (and covers any imperfections in the top of the bars).
• Granulated sugar: In the filling, it balances out the tartness of the lemon and ensures that the filling is smooth since the sugar dissolves in the lemon juice.
• Lemon juice: We use a lot to add tons of fresh lemon flavor. As it bakes, the taste intensifies, so avoid bottled juice in favor of freshly-squeezed. And strain out the pulp and seeds before measuring, to make sure you have enough.
• Lemon zest: Adds extra lemon flavor since it contains all of the essential lemon oils. Be sure not to grate down all the way to the bitter white pith.
• Butter: Brings the shortbread crust together, provides buttery flavor and richness, and makes the crust crisp on the outside.
• Eggs: Thicken and bind the custard filling, setting into a creamy structure that holds as the bars cool.
• Salt: Balances the sweetness and brightens the other flavors.
• Baking powder: Gives the filling a bit more rise for a slightly lighter-textured custard.

How to make gluten free lemon bars (step by step photos)

To make these bars, you have to place the pan in the oven twice. This visual guide includes an explanation of the reason behind each step in the recipe. For full ingredient amounts, see the recipe card below.

For the crust: whisk dry ingredients
Whisk together all of the dry ingredients to make the shortbread-style cookie crust of these bars, including the flour blend, confectioners' sugar, salt, and lemon zest. The lemon zest will stick to itself, so keep whisking until everything is fully combined, with no clumps.

Add melted butter
The only remaining ingredient to bring the crust together is 9 tablespoons of melted unsalted butter. I melt the butter in the microwave on medium power, stopping just before it's fully liquid, as the residual heat will melt the rest and it cools more quickly and doesn't cook, losing moisture.

Mix into clumps
I prefer to mix the butter into the dry ingredients with a fork to create large, fully incorporated clumps that are easy to scatter evenly in a fully lined and greased pan. To keep the parchment paper in place during baking, you can clip all 4 sides with small binder clips.

Smooth the crust
Use a small offset spatula or butter knife to press down on the cookie clumps, smoothing them into an even layer on the bottom of the prepared pan. Don't press down too hard or you'll compress the crust and it won't bake as evenly.

Parbake it
To seal the crust and ensure it doesn't get soggy once you add the liquid filling, partially bake it first at 325°F for about 15 minutes. As it parbakes, the crust will turn shiny as the ingredients melt, then lose its shine and the crust will turn very pale and matte. Let it cool briefly while you make the filling mixture. This also prevents you from having to overbake the filling just to get the crust firm enough to hold it.

For the filling: whisk dry, then wet ingredients
In a separate mixing bowl, whisk together the remaining 2/3 cup of the flour blend, granulated sugar and a bit of baking powder. Whisk fully to avoid any pockets of leavening which will cause uneven baking and can taste off.

Add 2/3 cup of fresh-squeezed and strained lemon juice and 4 eggs to the mixing bowl, and whisk to combine. Whisk fully to ensure that everything is smooth and fully combined, and the eggs well-beaten, but not so roughly that introduce too many air bubbles.

Combine crust and filling
Pour the smooth filling into the partially baked crust. It will be thin enough to smooth itself into an even layer. Tap the bottom of the pan a few times on the counter to help break as many air bubbles as possible for a filling that bakes as smoothly as possible.

Finish baking the bars
Bake the crust and filling together for about 25 minutes. The filling may seem like it's going to remain liquid for the first 18 to 20 minutes, until it finally appears set. When it's done baking, the filling will have begun to pull away from the sides of the pan, will look uniformly risen across the top, and will only jiggle a bit in the center when you shake the pan gently back and forth, much like gluten free cheesecake.

Chill and slice
Remove the baked bars from the oven, place them on a wire rack, and let them cool in the pan for at least 20 minutes. This allows the pan to release any residual hot air from the oven so you don't trap condensed steam, making the bars soggy. Refrigerate the bars for at least 2 hours to allow the egg custard to set enough to allow you to slice it.

Expert tips

Use fresh lemon juice

Like in our gluten free lemon pie, bottled lemon juice tends to taste bitter, and the heat of baking intensifies flavors. If the flavor isn't great at the start, it will be worse after baking. Conventional lemons are available year-round, and there are even seedless ones that have more juice per lemon. Be sure to strain any pulp and seeds away before you measure the 2/3 cup of juice you need.

Whisk the filling fully, but gently

The filling mixture is quite thin, since it starts out as mostly liquid, then thickens in the oven as the eggs set with some stability added by the added flour. If you whisk the filling too vigorously, you'll create more air bubbles in the mixture which will break through the surface during baking.

If you've created too many bubbles, just let the filling sit for a while to allow the bubbles to break through, tapping the filling flat on the counter to help them burst. You can't eliminate every bubble though, so don't stress.

Allow for setting time

The lemon filling slices cleanly on top of the shortbread crust, but only if you allow it enough time to set in the refrigerator. Chilling allows the egg-based filling to set so that it's firm enough to slice.

Ingredient substitutions

Here are my suggestions for how you might be able to avoid some of the ingredients in these bars, and where you can't:

Dairy free

For the butter in the crust, I recommend using half Spectrum brand nonhydrogenated vegetable shortening and half block-style vegan butter to mimic the flavor profile and moisture content of dairy butter. For vegan butter, I like Melt or Miyoko's brand.

Egg free

There are 4 eggs in this recipe. I don't believe that you can replace all 4 of them with an egg substitute and achieve anything like the texture of these smooth, creamy custardy bars.

Lemon alternatives

In place of freshly squeezed lemon juice, try lime juice or orange juice, along with the corresponding zest.

Storage suggestions

These bars can be stored in a sealed container in the refrigerator for 3 to 5 days. If you've already dusted them with confectioners' sugar, it will likely absorb into the bars so you'll have to dust them again before serving.

For longer storage, freeze the bars uncovered just until firm (about 1 hour), then wrap each bar individually with plastic wrap for up to 3 months. They won't freeze solid, so they'll defrost quickly even in the refrigerator. Before serving, dust with confectioners' sugar.

FAQs

More lemon dessert recipes

Here are a few more of my favorite gluten free lemon dessert recipes.

• Gluten Free Lemon Cookies – Buttery-rich and light, these delightful lemon cookies melt in your mouth, and call for only 15 minutes of prep time.
• Gluten Free Lemon Brownies – The chewy consistency of a brownie with the bright flavor of citrus.
• Gluten Free Lemon Cake – If you've ever had the lemon cake at Olive Garden, try this tender, lemon-rich copycat recipe.