Easy Sourdough Lemon Bars (Discard Recipe)
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These Sourdough Lemon Bars are the perfect springtime treat and they couldn’t be easier to make! Zingy and tart lemon custard filling tops a sourdough shortbread crust that is light, buttery and melts in your mouth.
Made with only 7 simple ingredients, this quick sourdough dessert is the perfect addition to Easter brunch or Mother’s Day celebration. Finish them off with a dusting of powdered sugar and be ready to watch them disappear!
I originally published this recipe back in 2024. Since then, I have updated it with fresh photos, adjusted the recipe to create a more-lemon forward custard filling, and extra success tips for consistently excellent results.
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Why You’ll Love This Recipe:
Bright and Fresh
- Bright and Fresh: Is there anything more bright and refreshing than the taste or smell of lemon? Just like my Sourdough Lemon Loaf, these Sourdough Lemon Bars have the perfect balance of tartness and tanginess – a sourdough treat you’ll want to make all spring long!
- Quick Recipe: This is the perfect dish to make in a pinch! Made with pantry staples and in two bowls , these Sourdough Lemon Bars are the perfect addition to any Easter brunch or Mother’s Day celebration. Better yet, they can be prepared ahead for even more convenience.
- Simple: What makes classic lemon bars so delicious is their simplicity! With just 7 ingredients, you are able to awaken your tastebuds with a perfectly easy, tart, and sweet treat, now with the goodness of sourdough!
Ingredients You’ll Need
* To find precise measurements, scroll to the bottom of this post to find the recipe card*
Sourdough Crust
- Unsalted Butter – In order to create a buttery shortbread crust, you need butter! Use melted butter for easy mixing.
- Powdered Sugar – Brings the perfect sweetness to the crust without any gritty texture.
- Flour – All-purpose flour is what I used to make this tender crust.
- Sourdough Discard – For sweeter recipes like these sourdough bars, I like to use 1–2-day-old discard. You can use active sourdough starter, just measure the same amount in grams.
Lemon Filling
- Large Eggs – Brings structure to the lemon filling and helps it to set properly.
- Sugar – The needed sweetness to balance the tartness from the lemon juice.
- Sourdough Discard – This helps thicken the lemon curd! Just as before, use fresh sourdough discard or the same amount of active sourdough starter.
- Lemon Juice – The star ingredient! That being said, I highly suggest using freshly squeezed lemon juice for the best lemon flavor. Don’t use lemon concentrate. I used regular lemons in this recipe, instead of others like Meyer lemons.
How to Make Sourdough Lemon Bars
- Preheat the oven to 350°F and line a 9×13 baking dish with parchment paper. Set aside.
- In a medium bowl, add the melted butter and sourdough discard. Whisk until combined. Set aside.
- In a separate bowl, whisk together the flour and the powdered sugar. Add the wet ingredients to the flour mixture and mix until it resembles pie dough.
- Pour the dough into the prepared baking dish and gently press the dough with your hands. Bake for 25-30 minutes, or until the shortbread base is lightly golden brown.
- In a large bowl, whisk the sourdough discard, sugar, eggs, lemon juice and lemon zest together until smooth.
- Once the crust is baked, poke with a fork, pour the wet ingredients over the warm base layer and return to the oven. Continue to bake for another 25-30 minutes.
- Remove the Sourdough Lemon Bars from the oven and place on a wire rack to cool. Once cooled, dust with powdered sugar, if desired.
McKenna’s Helpful Tips
- Line the baking pan with parchment paper: Be sure not to skip this step. Parchment paper makes pulling out the lemon bars after baking a breeze!
- Skip the lemon concentrate: I know it’s convenient, but for the best tasting lemon bars, use freshly squeezed lemon juice.
- Wipe your knife after each cut: Wiping your knife with a damp paper towel after each cut gives you perfectly clean lemon bars.
How to Store
Store leftover Sourdough Lemon Bars in an airtight container or covered in plastic wrap and store in the refrigerator for 4-5 days.
To freeze, cut into individual slices and wrap with plastic wrap, then store in a freezer-safe bag in the freezer for 2-3 months. When ready to enjoy frozen lemon bars, transfer them to the refrigerator and allow them to thaw overnight.
FAQs
Can I use bottled lemon juice instead of fresh for lemon bars?
Since lemon is the star ingredient of this recipe, you want to use real lemon juice. Lemon juice from a bottle or concentrate can be handy in a pinch, but for the best flavor, I highly recommend using freshly squeezed lemon juice.
Why are there small, white bubbles on top of my Sourdough Lemon Bars?
Bubbles forming on top of your Sourdough Lemon Bars is normal. These bubbles are from whisking the eggs. While baking, the bubbles will rise to the top of the lemon curd. These can, however, brown lightly while baking. Luckily they can be covered up nicely with powdered sugar.
Can I use active starter instead of sourdough discard?
Absolutely! Just be sure to use the same amount in grams.
Sourdough Lemon Bars Recipe
Yield: 15 Bars
These Sourdough Lemon Bars are the perfect lemon bars, but now with a delicious twist! Zingy, bright, and tart lemon filling tops a sourdough shortbread crust that is light and buttery. The perfect sweet treat to brighten anyone's day.
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Ingredients
Sourdough Crust
- 170 grams unsalted butter, melted 3/4 cup
- 120 grams sourdough discard 1/2 cup
- 250 grams all-purpose flour 1 3/4 cups
- 60 grams powdered sugar 1/3 cup
- pinch of salt
Lemon Filling
- 6 eggs beaten
- 425 grams sugar 2 cups + 2 Tablespoons
- 150 grams sourdough discard 1/2 cup + 2 Tablespoons
- 175 grams lemon juice, freshly squeezed 3/4 cup
- zest of one lemon
Instructions
- Preheat the oven to 350 degrees F. Prepare a 9×13 baking dish with parchment paper, leaving enough overhang for easy removal of the bar after baking for easy slicing. Set to the side.
- In a medium bowl, add the melted butter and sourdough discard. Whisk until combined. Set aside.170 grams unsalted butter, melted, 120 grams sourdough discard
- In a separate bowl, whisk together the flour, powdered sugar and salt. Add the wet ingredients to the flour mixture and mix until it resembles pie dough.250 grams all-purpose flour, 60 grams powdered sugar, pinch of salt
- Pour the dough into the prepared baking dish and gently press the dough with your hands, trying to press everything as even as possible and to the edges! Bake for 25-30 minutes, or until the shortbread base is lightly golden brown. I prefer a more crisp sourdough shortbread, so I tend to bake the full 30 minutes.
- While the crust is baking, prepare the lemon layer.
- In a large bowl, add the sugar and lemon zest. Rub the lemon zest and sugar in between your clean hands. This helps to extract the lemon oils from the zest, giving these lemon bars even more delicious lemon flavor!425 grams sugar, zest of one lemon
- To the lemon sugar, add the sourdough discard and whisk until combined. Then add in the eggs and whisk until smooth. Finally pour in the freshly squeezed lemon juice and mix by hand until well-blended.6 eggs, 150 grams sourdough discard, 175 grams lemon juice, freshly squeezed
- Once the crust is baked, remove the pan from the oven. Poke the shortbread with the prongs of a fork all around its surface. This helps the lemon custard to adhere to the sourdough shortbread.
- Pour the wet ingredients over the hot base layer and return to the oven. Continue to bake for another 25-30 minutes or until the lemon filling has set and has the iternal temperature of 180 degrees F.
- Remove the Sourdough Lemon Bars from the oven and place them on a wire rack to cool for at least an hour and then for two hours in the fridge for it to set. The chill time is crucial for allowing the filling to set and for easy slicing. Before serving, dust with powdered sugar, if desired. Slice and enjoy!
Notes
Ingredients You’ll Need
Sourdough Crust
- Unsalted Butter – In order to create a buttery shortbread crust, you need butter! Use melted butter for easy mixing.
- Powdered Sugar – Brings the perfect sweetness to the crust without any gritty texture.
- Flour – All-purpose flour is what I used to make this tender crust.
- Sourdough Discard – For sweeter recipes like these sourdough bars, I like to use 1–2-day-old discard. You can use active sourdough starter, just measure the same amount in grams.
Lemon Filling
- Large Eggs – Brings structure to the lemon filling and helps it to set properly.
- Sugar – The needed sweetness to balance the tartness from the lemon juice.
- Sourdough Discard – This helps thicken the lemon curd! Just as before, use fresh sourdough discard or the same amount of active sourdough starter.
- Lemon Juice – The star ingredient! That being said, I highly suggest using freshly squeezed lemon juice for the best lemon flavor. Don’t use lemon concentrate. I used regular lemons in this recipe, instead of others like Meyer lemons. You could also substitute the lemon juice for orange juice or lime juice instead!
FAQs:
Can I use bottled lemon juice instead of fresh for lemon bars?
Since lemon is the star ingredient of this recipe, you want to use real lemon juice. Lemon juice from a bottle or concentrate can be handy in a pinch, but for the best flavor, I highly recommend using freshly squeezed lemon juice.Can I use active sourdough starter instead of discard?
Absolutely! Just be sure to use the same amount in grams.
Why are there small, white bubbles on top of my Sourdough Lemon Bars?
Bubbles forming on top of your Sourdough Lemon Bars is normal. These bubbles are from whisking the eggs. While baking, the bubbles will rise to the top of the lemon curd. These can, however, brown lightly while baking. Luckily they can be covered up nicely with powdered sugar. This recipe card was updated on 03/22/26.Nutrition
Serving: 1bar | Calories: 311kcal | Carbohydrates: 49g | Protein: 5g | Fat: 11g | Saturated Fat: 6g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 3g | Trans Fat: 0.4g | Cholesterol: 90mg | Sodium: 27mg | Potassium: 58mg | Fiber: 1g | Sugar: 33g | Vitamin A: 379IU | Vitamin C: 5mg | Calcium: 16mg | Iron: 1mg
Tried this recipe?Please leave a comment on the blog or share a photo on Instagram!
Absolutely the best lemon bars …very addicting! Your instructions were easy to follow, and very detailed. They freeze great and will definitely be my go to recipe for lemon bars. Thanks for sharing!
I’m so glad you loved them and found the instructions easy to follow. And that’s great to hear they freeze well too—that’s such a helpful tip. I really appreciate you taking the time to share this, and I’m honored they’ll be your go-to lemon bars!
Im a little bit deceived because I expected a really good lemon taste, but it doesn’t taste lemon at all
Thank you for the feedback—I really appreciate you sharing that. Lemon flavor can vary quite a bit depending on the freshness and strength of the lemons used. If you’re looking for a stronger lemon flavor, you can add a bit of lemon zest, which really boosts that bright, citrusy taste!
My sister and I made this today, however, the sweet crust that formed on top, crumbled . Everything under was cooked , nothing raw. We waited till it was cool enough to remove from the dish and it crumbled. What did we do wrong? Note: The crusty foam on top is really delicious. 😋
Hi Michelle! Thanks so much for trying the recipe—and I’m glad you and your sister enjoyed that crusty top (it really is delicious 😋)! It sounds like they may have been just a touch underbaked or possibly cooled too quickly, which can cause that delicate top layer to crack and crumble when cutting. Next time, you could try baking for just a few more minutes and letting them cool completely at room temp before slicing. I’m so happy everything underneath was fully baked though—that’s a great sign!
My lemon bars were still jiggly so I put them in for an extra 10 min and the crust became hard and inside is raw? Do you know why?
Thanks so much for trying the recipe! It sounds like the filling may not have fully set before the crust started to over bake—this can sometimes happen if the oven runs a bit hot or the filling wasn’t fully mixed. For next time, I recommend covering the bars loosely with foil if you need to bake them longer so the crust doesn’t get too firm, and keeping an eye on the center—it should have a slight jiggle, but not be liquidy. I know how frustrating that can be, and I really appreciate you giving them a try!
I made this recipe today and it definitely took longer to set in the oven. I covered with foil and reduced temp to 325 to finish. I also wish it had more of a lemon kick.
Hi Jamie, thanks so much for trying the recipe and for your feedback! Oven times can definitely vary, so I’m glad you adjusted and got it to set—that’s great baking intuition! If you’re craving more of a lemony kick, you can add a bit more zest.
Hello! How long can I keep lemon bars out of the fridge? Will they hold stable sitting on a desert table
Hi Carolyn! Lemon bars are best stored in the fridge since they have an egg-based filling, but they’ll hold up fine on a dessert table for a few hours—about 2–4 is usually safe. Just keep them out of direct sun or heat, and they should stay stable and delicious. Hope they’re a hit!
I got a weird light brown crust on top of my filling while the under layer was still raw. Weird!
Hi Lucy! So sorry to hear that the shortbread crust was raw. The light brown crust on top is normal. It happens due to the sugars crystalizing while the lemon bars are baking.
I am allergic to eggs but Hubby took them to his team mates at work and they were a huge hit. One girl made a video while eating one and loved them.
Amazing! So glad everyone enjoyed them 🙂
Hello, the recipe calls for 3/4c melted butter (86g), but 3/4c of butter is way more than 86g, more like 160g. For this do you follow grams or cups?
Hi Abbey! Thank you so much for catching my typo! It has been correct to 3/4 c (170g) of melted butter.
Made these twice, following the recipe exactly, and both times the lemon curd does not set! What am I doing wrong?
Hi Alessandra! I’m so sorry to hear that. My guess is they may not have been baked long enough. The filling should jiggle slightly in the centre when you remove it from the oven, but the edges should be set and more firm. If it’s too jiggly, it won’t set properly.
Can the crust be long fermented for sourdough benefits ?
Absolutely!