Learn the best gluten-free baking tips for making homemade lemon squares with a tender, flaky crust. This no-fail gluten-free lemon bars recipe uses a simple technique for a perfectly-set lemon custard on a crisp, buttery base, all baked to perfection. The ideal sweet and tangy citrus topping sits on a classic shortbread crust, which can be quickly blended together in a food processor or mixer.
Lemon bars Made With gluten-free flour
Enjoy classic lemon bars again, even better than the old fashioned one’s mom made! This gluten-free lemon bars recipe includes a foolproof trick for a lemon topping that is slightly jiggly and gooey, yet solid enough to cut into squares and serve.
When I was testing this recipe I knew baking the lemon topping with the crust would not yield the best results. Gluten-free baked goods require a slightly longer baking time since fat and moisture has a harder time absorbing into the starches.
Therefore, the creamy lemon custard comes together on the stove first to begin the cooking process and slightly thicken the filling. The gluten-free shortbread crust partially bakes before spreading on the filling so both layers finish with the exact texture you’d hope for in homemade lemon squares – a combination of soft and gooey with crisp and flaky.
When developing the flavor in lemon desserts, whether it’s a homemade gluten-free lemon bundt cake or a fresh lemon blueberry sheet cake, there needs to be a balance of tangy citrus tartness with ideal amount of sugar. Therefore these gluten-free dessert bars use the juice of 4 lemons plus zest to amplify taste.
To ensure a solid, yet flaky crust, I used another baking trick. Blending the butter in gradually, either in a food processor or stand mixer, helps incorporate the fat fully with the gluten free flour. This ensures the shortbread is crisp and tender instead of dry and crumbly.
Read on to discover how to make this easy gluten-free lemon bar recipe, step-by-step. Included are ingredient notes, substitutions, a dairy-free modification, plus how to make gluten-free lemon squares with an alternative almond flour crust as well.
Ingredient notes
For the creamy lemon filling plan on using about 4 fresh lemons juiced and zested. I have not tested the recipe with sugar substitutes, but using a dairy-free butter, such as Earth Balance should work fine.
- Gluten-free flour blend – I use and recommend Cup4Cup Gluten Free Flour because the added cornstarch in the blend eliminates any potential grittiness. When making this crust or homemade gluten-free shortbread cookies, a quality GF all-purpose flour is crucial because there are so few ingredients.
- Unsalted butter – This is used in the crust for a crisp texture and in the custard, which combines with the egg yolks to enhance richness.
- Eggs – You will need 3 whole eggs, plus egg yolks. This ensures there is a thick layer of lemon filling, plus helps bind and set it.
- Lemons – Use only freshly squeezed juice for best lemon flavor. I don’t recommend concentrated lemon juice which will be too bitter. Similar to these bright, fresh gluten-free lemon poppy seed muffins, both the juice and zest are used to add flavor.
- Cream of tartar – This ingredient has two roles in lemon squares. It helps bring out the tanginess and also stabilizes the eggs for structure.
How to make Gluten-free lemon bars recipe
(Below shows step-by-step photos and modified instructions. For the complete recipe, along with ingredient amounts, scroll down to the recipe card.)
To make easy gluten-free lemon bars, begin by making the crust so it has time to cool partially before topping with the fresh lemon filing. The lemon custard first thickens on the stove top, then finishes in the oven, to make sure the bars set every time.
(Note: This is a step-by-step tutorial with pictures. For more specific instructions, along with ingredient amounts, see the recipe card at the bottom of the post.)
- For the crust, use a stand mixer with paddle attachment or food processor. This helps fully incorporate the butter so the crust doesn’t become crumbly. In the large bowl of the mixer or bowl of a food processor, blend the flour, sugar, and salt on low speed.
- Add the softened butter to the dry ingredients, one tablespoon at a time, blending completely between each addition.
- Line a 8X8″ pan with a large piece of aluminum foil, pressed firmly to the bottom and the sides with enough overhang to lift the bars out after baking. Press the gluten-free shortbread into the prepared baking pan firmly.
- Bake in a 350ºF oven for 20-25 minutes, or until lightly golden brown. Cool slightly while the filling is made.
- In a medium saucepan whisk together the filling dry ingredients – sugar, flour, cream of tartar, and salt. Add the eggs, egg yolks, lemon zest, and fresh lemon juice and whisk to combine.
- Cook over medium-low heat, whisking constantly, until the mixture thickens and reaches a temperature of 160ºF, about 5-7 minutes. (I use my favorite instant read thermometer to check quickly.)
- Remove from the heat and stir in the cold butter. Pour the hot filling over the baked crust. Return to the oven for 10-12 minutes, or until the edges are raised and the filling barely jiggles when the pan is gently shook.
- Cool the bars to room temperature, then chill for 2 hours, dust with powdered sugar, and slicing with a sharp knife to serve.
Using almond flour to make lemon bars
Instead of using gluten free flour for the crust, there are other options for a grain-free bar. Replace the shortbread with either almond flour pie crust or pecan crust recipes.
For best results, use a 9X9 inch pan instead of 8X8 inch. This will give a better proportion of crust to filling. Also, line the pan with a large piece of parchment paper, instead of foil, to lift the squares out after the filling has cooled and chilled.
Bake the crust completely, according to the alternative crust instructions, before topping with lemon curd filling. The flour in the filling may be replaced with cornstarch or arrowroot starch to thicken.
An almond flour crust or nut crust will not be as solid as a shortbread crust, but will still have a great flavor and a tasty way to enjoy grain-free dessert with traditional lemon bars taste!
Substituting limes for lemons
If you would like to make GF lime bars, replace the fresh lemon juice and zest with equal amounts of lime juice. Just like with the lemon, freshly squeezed is best.
Dairy-free adaptation
Replace the butter with a dairy-free butter (such as Earth Balance butter sticks). However, plant-based butter is a little saltier so I recommend omitting the salt in the recipe.
how to tell when they are done baking
This recipe has a shortened baking time because the custard filling comes together on the stove first. While this is an extra step, it does take out some of the guesswork of when the lemon square are done.
The bars should have a raised edges and the middle should be set. It will still jiggle a little when the pan is shook, but shouldn’t slosh around.
For best results, cool the bars completely on a wire rack and then at least 2 hours before cutting and serving.
Storing and Serving Tips
After the bars have completely cooled, they will need to chill for 2 hours to fully set. After serving, any leftovers should be refrigerated in an airtight container. Upon sitting, the powdered sugar will seep into the filling, so you may want to dust them again upon serving.
When slicing the bars the filling will have a tendency to stick to the knife. For clean cuts, run the knife under hot water between slices and carefully wipe with a clean dish towel.
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Fresh Gluten-Free Lemon Bars with Shortbread
Equipment Needed
Ingredients
Gluten-Free Shortbread Crust
- 1 ⅓ cup gluten free all purpose flour I use and recommend Cup4Cup
- ⅓ cup granulated sugar
- ¼ teaspoon salt
- 8 tablespoons unsalted butter, softened and cut into 8 pieces
Lemon Filling
- 1 cup granulated sugar
- 2 tablespoons gluten free all purpose flour I use and recommend Cup4Cup
- 2 teaspoons cream of tartar
- ¼ teaspoon salt
- 3 large eggs + 3 egg yolks
- 2 teaspoons grated lemon zest
- ⅔ cup fresh lemon juice about 4 lemons
- 4 tablespoons unsalted butter cut in 4 pieces
- powdered sugar for serving
Instructions
- Preheat the oven to 350ºF. Line an 8X8" pan with a large piece of foil, pressed firmly to the bottom and the sides with enough overhang to lift the bars out after baking. Set aside.
- For the crust, use a food processor or stand mixer fitted with paddle attachment. On low speed combine the flour, sugar, and salt.1 ⅓ cup gluten free all purpose flour,⅓ cup granulated sugar,¼ teaspoon salt
- Add the softened butter to the dry ingredients, one tablespoon at a time, blending completely between each addition. The dough should pull away from the sides of the bowl and come together without any dry crumbs.8 tablespoons unsalted butter,
- Pour in the prepared baking pan, pressing firmly into an even layer. Bake for 20-25 minutes, rotating halfway through, until lightly golden brown. Remove from oven, leaving oven on, while the filling is prepared.
- For the filling, use a medium saucepan to whisk together the sugar, flour, cream of tartar, and salt. Add the eggs, egg yolks, lemon zest, and lemon juice. Whisk to combine.1 cup granulated sugar,2 tablespoons gluten free all purpose flour,2 teaspoons cream of tartar,¼ teaspoon salt,3 large eggs + 3 egg yolks,2 teaspoons grated lemon zest,⅔ cup fresh lemon juice
- Cook over medium-low heat, stirring constantly, until the mixture until the mixture thickens and reaches a temperature of 160ºF, about 5-7 minutes. (I use my favorite instant read thermometer to check quickly.)
- Remove from the heat and stir in the butter. Pour the hot filling over the baked crust.4 tablespoons unsalted butter
- Return to the oven for 10-12 minutes, or until the edges are raised and the filling barely jiggles when the pan is gently shook. Cool the bars to room temperature, then chill for 2 hours in the pan. Lift the bars out of the pan by the foil handles and cut into bars. Dust the tops with powdered sugar and serve. Refrigerate leftovers in an airtight container.
Recipe Notes
How to tell when lemon bars are done baking
The bars should have a raised edges and the middle should be set. It will still jiggle a little when the pan is shook, but shouldn’t slosh around.For best results, cool the bars completely on a wire rack and then at least 2 hours before cutting and serving.
Storing
Store cut lemon bars in the refrigerator in an airtight container. Upon sitting, the powdered sugar will seep into the filling, so you may want to dust them again upon serving. Crust recipe adapted from The How Can it Be Gluten Free Cookbook and filling adapted from Cook’s IllustratedNutrition
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Stefanie says
These were phenomenal, and some of the best Lemon Bars I’ve ever had, GF or not. Everyone at my Super Bowl party raved and said they would never have known they were GF. I loved that lemon was the true star and they weren’t overly sweet, and the crust, wow, such a perfect, short crumb.
Do you think that crust recipe could be used for making shortbread cookies if I just added some vanilla or other flavoring? I miss buttery, crumbly shortbread cookies (i.e. Walkers) :o)
Thank you so much for this and all your other wonderful recipes!
Melissa Erdelac says
Thanks so much, Stephanie! I think the shortbread recipe would be a good place to start, but would need some more tweaking to get that exact texture of Walkers. I’ll put it on my recipe list to play around with! Stay tuned…
Best,
Melissa
Peg says
II am looking for the almond flour adapted recipe, but cannot find it. (I wanted to make these for Father’s Day in 4 days.)
Melissa Erdelac says
Hi Peg,
You can use this crust recipe to make almond flour ones! Just press into a 9X9-inch pan.
Best,
Melissa
Jasmine says
Made these last night. I omitted the cream of tartar and halved the butter in the custard. They turned out incredible. I will make them again the same way!
Melissa says
Hi Jasmine,
Thank you so much for sharing! I’m glad your recipe adaptation worked out so well 🙂
Best,
Melissa