Sourdough Lemon Bars

These sourdough lemon bars are bright, tangy, and perfectly balanced, with discard tucked into both the buttery shortbread crust and the lemon filling. The result is a bar that’s crisp on the bottom, smooth in the center, and just sweet enough to let the lemon shine.

The sourdough doesn’t make these taste “sour” in the way you might expect. Instead, it deepens the flavor and softens the sweetness, giving the lemon filling a little extra complexity and the crust a subtle tenderness. If you love lemon desserts and you’re looking for a creative way to use discard, this is a beautiful place to start.

Why you’ll love this recipe

• Bright lemon flavor with balanced sweetness – The sourdough discard gently rounds out the sharp citrus notes so the bars taste vibrant but not overpowering.
• Discard in both layers – Using starter in the crust and the filling adds texture and depth without making the recipe complicated.
• Sliceable, shareable, and freezer-friendly – These bars cut cleanly once chilled and are perfect for gatherings, gifting, or keeping on hand for a quick dessert.

If you love the simple nature of these sourdough lemon bars, there are a few other straight forward recipes worth trying next. Sourdough apple crisp offers that dump and bake simplicity and delicious results. If you enjoy sliceable desserts like this, you might also love sourdough chocolate chip cookie bars. Another great choice to share with others is sourdough coffee cake. Together, these recipes show just how versatile sourdough can be in everyday desserts.

How to make lemon bars with discard

This is a brief overview of how the recipe so you can get an idea of what the steps before you start baking. For the full set of written directions, including ingredient amounts, please scroll down to the recipe card below.

Step One: Make the crust

Preheat the oven and line a square baking pan with parchment paper.

In a bowl, cream the butter and sugar until light and fluffy. Mix in the sourdough discard, vanilla, and salt, then add the flour. Mix until the dough looks chunky like wet sand. It should press together easily and be soft.

Press the dough evenly into the prepared pan. Poke the dough with a fork all over and then bake until lightly golden at the edges.

Step Two: Make the Filling

In a bowl, run the sugar and lemon zest together until the sugar is yellow in color and well scented with the lemon zest. Add in the eggs whisk together until smooth. Add in the sourdough discard and whisk until smooth (I find it’s best to use room temperature discard here). Add fresh lemon juice, then whisk in until fully incorporated. The filling should be smooth and pourable and liquidy.

Pour the lemon mixture over the crust as soon as you pull it from the oven.

Step Three: Baking

Bake the bars until the lemon filling is set and doesn’t jiggle in the middle when you wiggle the pan.

Allow to cool in the pan at room temperature until it is room temperature, and then move to the fridge to chill fully, at least two hours or overnight.

Before serving, dust the tops of the lemon bars with powdered sugar.

Storage information:

Store the lemon bars, covered, in the fridge for up to 3 days.