The Best Sourdough Lemon Bars (so easy!)

This is the kind of dessert you’ll want to bring to every spring gathering! The filling is tart yet sweet, and the shortbread crust is really soft, but durable enough to hold the lemon custard filling, creating the perfect balance of flavors and textures. Simple to make but full of flavor, these lemon bars are an irresistible dessert that will have everyone asking for the recipe. 

If you love bright flavors, be sure to also try my Lemon Blueberry Sourdough Focaccia and Strawberry Lemon Sourdough Scones. 

Why you will love this recipe

• Only 7 simple ingredients –  You only need a few simple ingredients to make this easy Sourdough Lemon Bar recipe. 
• Great use for sourdough discard – This Sourdough Lemon bar uses discard as a thickener and stabilizer for the filling as well as in the shortbread crust. 
• Bright, fresh flavors – Just like my Lemon Poppy Seed Sourdough Muffins, the bright lemon is the perfect flavor for spring or summer baking. 
• Easy recipe for special occasions – These Sourdough Lemon Bars are sure to be the talk of the party! They are the perfect dessert for Easter Brunch, Mother’s Day, or any other spring gathering. 

Important Ingredients and Substitutions

• Sourdough discard – I recommend using fresher discard so that the flavor is not too overpowering in the filling. Active sourdough starter will also work if you do not have discard. 
• Lemon – Lemon juice and lemon zest create the bright lemon custard filling. I recommend using fresh lemon juice for the best flavor. If you have extra lemons make my Lemon Blueberry Sourdough Bread.
• Sugars – You will need powdered sugar for the crust and to dust on top of the bars, as well as granulated sugar for the filling. 
• Butter- I use salted butter, but if you use unsalted butter, I recommend adding 1/4 teaspoon of salt to the dough.

See all the ingredients and amounts in the recipe card below.

Instructions to make Sourdough Lemon Bars

Step 1 – Make the shortbread crust

Melt the butter and mix with the discard in a medium bowl. Add the powdered sugar and flour and mix to combine. 

Step 2 – Bake the crust

Grease or line a 9×9 baking pan and press the shortbread cookie dough into the bottom of the pan. Make sure to press the dough all the way into the corners. You can use a piece of parchment paper to help press the dough down.

Bake the crust in a preheated 350℉ oven for 20 minutes.

Step 3 – Make the filling

While the crust bakes, make the filling. Add the sugar to a mixing bowl and zest the lemon. Rub the zest and sugar between your fingers to release the oils. 

Then whisk in the eggs, lemon juice, and discard until fully incorporated. Right before pouring it on the crust, whisk again to ensure it is all mixed up.

Step 4 – Bake

Pour the lemon filling over the hot crust and bake for 22-25 minutes. The top will look set and will have just a slight jiggle when it is ready.

Storage instructions

To store the Sourdough Lemon Bars, add them to an airtight container and store in the refrigerator for up to one week.

You can also freeze the lemon bars for up to 3 months. I recommend cutting the lemon bars into squares and then freezing the bars before adding the powdered sugar dusting on top. You can wrap them individually with plastic wrap so you can remove as many as you’d like at a time. To thaw, add the bars to the fridge overnight and then serve with a fresh dusting of powdered sugar.  

Recipe FAQ

More Sourdough Desserts

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Sourdough Strawberry Cheesecake Cookies

Sourdough Discard Recipes

The Best Sourdough Strawberry Shortcake Recipe

Sourdough Discard Recipes

Sourdough Carrot Cake (9×13 or Bundt pan)

Sourdough Breakfast Recipes

Strawberry Lemon Sourdough Scones

Tried the Sourdough Lemon Bars or another recipe from the site? I’d love to hear about it! Drop a star rating and share your thoughts in the comments. Can’t wait to see what you’re baking!