Sourdough Blueberry Crumb Bars
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Use up sourdough discard and make Blueberry Crumb Bars at the same time! These crispy sourdough shortbread bars are filled with a homemade blueberry filling!
If you’re looking for more crumb bars, be sure to check out some of my favorites like Chocolate Strawberry Crumb Bars or Cherry Pie Bars.
Table of Contents
These blueberry bars are another collab with my friend Hannah at Make It Dough! Every month we collaborate together on a recipe using sourdough or sourdough discard. Hannah really wanted to do something with blueberries this month because they are in season. So, I suggested crumb bars because I’m obsessed with them and they are a wonderful egg free dessert if you’re having an issue with eggs right now! And Hannah created a delicious version of these beloved bars!
These Blueberry Crumb Bars have a crispy sourdough shortbread crust that uses up sourdough discard to reduce waste! And you can use fresh blueberries, frozen blueberries, or even blueberry jam if you’re feeling lazy. They’re topped with the signature bits of shortbread on top and dusted with powdered sugar for a light and fruity treat you’ll love!
Why You’ll Love This Recipe
Uses Sourdough Discard: I love recipes that use up sourdough discard, and these blueberry bars do it so well!
Naturally Eggless: Sourdough discard actually makes a great egg replacer. These Blueberry Crumb Bars are naturally eggless as I use sourdough discard.
Flexible: You can use fresh or frozen blueberries for these Blueberry Crumb Bars. You can even use store bought blueberry jam for ease, or even other flavors of jam like strawberry, blackberry, apricot, cherry and more.
Ingredients
- Butter: I use organic salted butter as that’s my go to, but you can also use unsalted. If using unsalted, just add 1/2 teaspoon of salt to the recipe.
- Powdered Sugar: Using organic powdered sugar gives these blueberry bars a light and sweet sourdough shortbread crust. Also, they are dusted with it instead for a beautiful finish.
- Vanilla Extract: Be sure to use a high quality vanilla extract, not imitation.
- Lemon: Organic lemon zest is used inside the sourdough shortbread dough for added flavor and the juice is used in the blueberry filling. But, if you are using store bought blueberry jam, you can omit the lemon zest to make it easier, they’ll still be delicious!
- Sourdough Discard: You can use your sourdough discard straight from the fridge. Making these blueberry bars is a delicious way to reduce waste!
- All Purpose Flour: This provides stability in these Blueberry Crumb Bars because of the higher protein content compared to something like cake flour. So, the sourdough shortbread crust can successfully hold all the delicious blueberry filling without breaking because we’re using organic all purpose flour.
- Cornstarch: This helps bind the filling together and solidify the sugars with the blueberries, so it doesn’t become soggy in the oven. I always use organic cornstarch as corn is a crop that can be grown very poorly with GMOs, pesticides, and more.
- Blueberries: You can use fresh or frozen blueberries for these blueberry bars. And, if you’re feeling lazy, you can also use store bought blueberry jam or preserves instead of making the filling.
- Cane Sugar: You’ll need organic cane sugar if you’re making your own blueberry filling. If you’re using store bought jam, you won’t need this ingredient.
Tools Needed
- Scale: Always use a digital food scale for the best results.
- Stand Mixer: I use my stand mixer for ease, but if you prefer to use a hand mixer you can also do that.
- Baking Pan: You’ll need an 8×8-inch baking pan, but if you only have a 9-inch baking pan that also works. You can also use a 8-inch or 9-inch round baking pan, it does not have to be square.
- Parchment Paper: I always use nontoxic parchment paper to ensure these blueberry bars come out easily.
- 3-Quart Pot: You’ll need a 3-quart pot to make the filling. (Unless you’re using store bought jam!).
- Spatula: You'll need a spatula to cook the filling.
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Step by Step Instructions
Step 1
Cut two pieces of parchment paper, about 8 by 15 inches, to create a sling for an 8-inch baking pan. Or you can use precut parchment paper like I’m using here. Set aside.
Step 2
To make the dough: In the bowl of a stand mixer fitted with the paddle attachment, cream the butter, powdered sugar, vanilla, and lemon zest together until light and fluffy, about 3 minutes.
Add the sourdough discard and mix until well combined. Last, add in the flour, cornstarch, and salt mix until a cohesive dough is formed.
Step 3
Press ¾ of the dough (you can just eyeball this!) into the bottom of the prepared pan, making sure to press it into the corners.
Wrap the remaining dough in a piece of plastic wrap. Refrigerate the pan and the remaining portion of dough (used for the topping) for at least 30 minutes.
Step 4
Preheat the oven to 350°F.
Step 5
To make the filling: While the dough chills, add the blueberries, cane sugar, cornstarch, and lemon juice to a small saucepan and stir together. Cook over medium/high heat until the blueberries begin to break down. Once the mixture boils, turn the heat down to low/medium and cook until the filling has thickened, about 15 minutes. Stir often to prevent the filling from burning.
Step 6
Spread the warm blueberry filling evenly over the shortbread dough, making sure to get the filling into the corners.
Step 7
Break the remaining portion of shortbread dough over the filling, leaving a few spots where the blueberry filling still peaks through.
Step 8
Bake the bars for 40 to 45 minutes or until the shortbread topping looks lightly browned.
Step 9
Allow the bars to cool completely, then sift powdered sugar on top. Cut into 16 bars (4×4).
Baker’s Tips
- Make sure your butter is soft before beginning the recipe.
- You can use unsalted butter if you prefer, just add 1/2 teaspoon of salt to the recipe.
- You can use fresh or frozen blueberries in the filling, both work.
- You can also use store bought blueberry jam if you’re feeling lazy. Also, any jam flavor will also work, try out strawberry, blackberry, cherry or apricot for different flavors! If you use jam, just mix in 1 teaspoon of cornstarch into the jam.
FAQ’s
Yes, this is a great recipe to make ahead of time. You can just leave them in the pan overnight, then cut the day of your party.
You can still make these! Just mix together 28 grams all purpose flour and 28 grams water in a small dish. Use this in place of sourdough discard. While it won’t have the same flavor, it will still be delicious!
Craving More?
Sourdough Blueberry Crumb Bars
Ingredients
Dough
- 226 grams salted butter (softened)
- 150 grams powdered sugar (sifted)
- 2 teaspoons vanilla extract
- 1 lemon (zest)
- 56 grams sourdough discard
- 300 grams all purpose flour
- 22 grams cornstarch
Filling
- 226 grams blueberries (fresh or frozen)
- 100 grams cane sugar
- 8 grams cornstarch
- 1 tablespoon lemon juice
Topping
Instructions
- Cut two pieces of parchment paper, about 8 by 15 inches, to create a sling for an 8-inch baking pan. Or you can use precut parchment paper like I’m using here. Set aside.
- To make the dough: In the bowl of a stand mixer fitted with the paddle attachment, cream the butter, powdered sugar, vanilla, and lemon zest together until light and fluffy, about 3 minutes.
- Add the sourdough discard and mix until well combined.
- Last, add in the flour, cornstarch, and salt mix until a cohesive dough is formed.
- Press ¾ of the dough (you can just eyeball this!) into the bottom of the prepared pan, making sure to press it into the corners.
- Wrap the remaining dough in a piece of plastic wrap. Refrigerate the pan and the remaining portion of dough (used for the topping) for at least 30 minutes.
- Preheat the oven to 350°F.
- To make the filling: While the dough chills, add the blueberries, cane sugar, cornstarch, and lemon juice to a small saucepan and stir together. Cook over medium/high heat until the blueberries begin to break down. Once the mixture boils, turn the heat down to low/medium and cook until the filling has thickened, about 15 minutes. Stir often to prevent the filling from burning.
- Spread the warm blueberry filling evenly over the shortbread dough, making sure to get the filling into the corners.
- Break the remaining portion of shortbread dough over the filling, leaving a few spots where the blueberry filling still peaks through.
- Bake the bars for 40 to 45 minutes or until the shortbread topping looks lightly browned.
- Allow the bars to cool completely, then sift powdered sugar on top. Cut into 16 bars (4×4).
- Store any leftover bars in a cool, dry place for up to 3 days.
Video
Notes
Nutrition
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Love that these use up sourdough discard to reduce waste!