Sourdough Lemon Bars

5 from 6 votes

These Sourdough Lemon Bars have a soft, buttery shortbread crust topped with a bright and tangy lemon custard filling. Finished with a light dusting of powdered sugar, they’re packed with fresh lemon flavor and the perfect balance of sweet and tart.

Prep Time15

Cook Time42

Total Time57

Course: Dessert

Cuisine: American

Servings: bars

Author: Emily Christensen

Equipment

9x9 pan

Ingredients

Shortbread crust

140 grams salted butter 10 Tablespoons
75 grams sourdough discard ⅓ cup
60 grams powdered sugar ½ cup
210 grams all-purpose flour 1 ½ cup

Filling

300 grams granulated sugar 1 ½ cup
1 zest of one large lemon
4 large eggs
75 grams sourdough discard ⅓ cup
75 grams freshly squeezed lemon juice ⅓ cup, 2 large lemons

Instructions

Preheat: Preheat the oven to 350℉
Make shortbread: Melt the butter and mix with the discard in a medium bowl. Add the powdered sugar and flour and mix to combine.
140 grams salted butter , 75 grams sourdough discard , 60 grams powdered sugar , 210 grams all-purpose flour
Add to pan: Grease or line a 9x9 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 shortbread: Bake the crust for 20 minutes.
Make filling: While the crust bakes, make the filling. Add the sugar to a mixing bowl and zest the lemon. Rub the zest and sugar together to release the oils.
300 grams granulated sugar , 1 zest of one large lemon
Add wet ingredients: Whisk in eggs, lemon juice, and discard until fully incorporated. Right before pouring it on the crust give it one last mix.
4 large eggs, 75 grams freshly squeezed lemon juice, 75 grams sourdough discard
Add filling: 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 like jello when it is ready.
Cool: Let the lemon bars cool and then chill in the fridge for 1-2 hours to finish setting.
Serve: Top with powdered sugar and cut into 9 squares.

Notes

Make sure to bring the crust all the way to the edges of the pan to ensure that the lemon custard doesn’t leak underneath the crust.
Use room temperature discard so that it is easier to mix in with the rest of the ingredients.
I recommend using fresher discard so it’s not too tangy in the filling.
Make sure the eggs are completely whisked when making the filling, because if not, they can cook like egg whites on top.
The lemon filling will seem very runny when pouring onto the crust, but it will set as it bakes.
Use fresh-squeezed lemon juice for the best flavor. You will need about 2 large lemons.
To store, refrigerate for 1 week or freeze for up to 3 months.

Nutrition