Sourdough Lemon Bars

Bright, Tangy Lemon Dessert with a Buttery Sourdough Shortbread Crust

If you love refreshing citrus desserts, sourdough lemon bars are a delightful treat that combines the vibrant flavor of lemons with the subtle depth of sourdough. These bars feature a buttery, tender shortbread crust made with sourdough discard, topped with a smooth, tangy lemon filling and finished with a light dusting of powdered sugar.

Sourdough baking has become incredibly popular in recent years, especially for home bakers who maintain a sourdough starter. Instead of discarding the extra starter during feeding, many creative recipes use sourdough discard in sweet treats like pancakes, cookies, cakes, and desserts. Lemon bars are one of the most delicious ways to use it.

The sourdough discard adds a gentle tang and complexity that balances the sweetness of the lemon filling. The result is a dessert that is bright, rich, and perfectly balanced between sweet and tart.

These homemade sourdough lemon bars are perfect for spring gatherings, afternoon tea, potlucks, holiday desserts, or simply enjoying with a cup of coffee.

What Are Sourdough Lemon Bars?

Lemon bars are a classic dessert consisting of two layers:

Buttery shortbread crust
Smooth lemon custard filling

In this version, sourdough discard is incorporated into the crust to add flavor and reduce food waste. The discard contributes a mild tang and helps create a slightly softer crust with deeper flavor.

The top lemon layer is made with fresh lemon juice, eggs, and sugar, creating a silky filling that contrasts beautifully with the crumbly crust.

Why You’ll Love This Recipe

Perfect Use for Sourdough Discard

If you maintain a sourdough starter, this recipe helps you use extra discard instead of throwing it away.

Bright and Refreshing Flavor

Fresh lemon juice and zest give these bars a vibrant citrus flavor.

Easy to Make

The recipe requires simple ingredients and straightforward steps.

Great for Sharing

Lemon bars slice beautifully and are perfect for parties or gatherings.

Key Ingredients

Understanding the ingredients helps ensure perfect results every time.

Sourdough Discard

Adds a mild tang and enhances the texture of the crust.

All-Purpose Flour

Provides structure for the shortbread crust.

Butter

Creates a rich, crumbly crust.

Sugar

Sweetens both the crust and lemon filling.

Fresh Lemons

Fresh lemon juice and zest give the filling its bright citrus flavor.

Eggs

Eggs help thicken the lemon filling and create a smooth custard texture.

Cornstarch

Helps stabilize the filling so it slices cleanly.

Powdered Sugar

Used as a final dusting for a classic lemon bar appearance.

Tips for Perfect Sourdough Lemon Bars

Use Fresh Lemon Juice

Freshly squeezed lemon juice provides the best flavor.

Do Not Overbake

The filling should be set but still slightly soft in the center.

Cool Completely Before Cutting

Allow the bars to cool fully so they slice neatly.

Line the Pan with Parchment

This makes removing the bars much easier.

Preparation Time

Prep Time: 15 minutes
Baking Time: 40 minutes
Cooling Time: 1 hour
Total Time: About 1 hour 55 minutes
Servings: 12–16 bars

Ingredients

For the Sourdough Crust

1 cup all-purpose flour
½ cup unsalted butter, melted
¼ cup sourdough discard (unfed starter)
¼ cup granulated sugar
¼ teaspoon salt

For the Lemon Filling

3 large eggs
1 cup granulated sugar
⅓ cup fresh lemon juice
1 tablespoon lemon zest
2 tablespoons all-purpose flour
1 tablespoon cornstarch
¼ teaspoon salt

For Topping

Powdered sugar for dusting

Instructions

Step 1: Preheat the Oven

Preheat your oven to 350°F (175°C). Line an 8×8-inch baking pan with parchment paper, leaving extra paper on the sides for easy removal.

Step 2: Make the Crust

In a mixing bowl, combine flour, sugar, and salt.

Add melted butter and sourdough discard. Mix until a soft dough forms.

Press the dough evenly into the bottom of the prepared baking pan.

Bake for 15–18 minutes until the crust is lightly golden.

Step 3: Prepare the Lemon Filling

In a medium bowl, whisk together eggs and sugar until smooth.

Add lemon juice, lemon zest, flour, cornstarch, and salt. Whisk until fully combined.

Step 4: Add the Filling

Remove the crust from the oven and pour the lemon filling evenly over the hot crust.

Return the pan to the oven.

Step 5: Bake the Lemon Bars

Bake for 20–22 minutes until the filling is set and no longer jiggly in the center.

Step 6: Cool Completely

Allow the lemon bars to cool at room temperature for about 1 hour. For cleaner slices, refrigerate for an additional 30 minutes.

Step 7: Slice and Serve

Lift the bars out using the parchment paper.

Dust the top with powdered sugar and cut into squares.

Serving Suggestions

Sourdough lemon bars are delicious on their own, but you can enhance them with simple additions.

With Fresh Berries

Serve with strawberries, raspberries, or blueberries.

With Whipped Cream

A dollop of whipped cream adds extra richness.

With Tea or Coffee

These bars pair beautifully with afternoon tea or espresso.

Storage Tips

Refrigerator

Store lemon bars in an airtight container for up to 5 days.

Freezer

You can freeze them for up to 2 months. Wrap individual bars tightly in plastic wrap.

Serving Tip

Let frozen bars thaw in the refrigerator before serving.

Nutritional Information (Per Bar – Approximate)

Calories: 180
Carbohydrates: 26 g
Protein: 3 g
Fat: 7 g
Saturated Fat: 4 g
Sugar: 18 g
Sodium: 90 mg

Why This Sourdough Lemon Bars Recipe Works

The sourdough discard adds depth and subtle tanginess to the buttery crust while reducing food waste. The lemon filling is bright, smooth, and perfectly balanced between sweet and tart.

The combination creates a dessert that is refreshing, rich, and beautifully textured, making it ideal for both casual gatherings and special occasions.