The BEST Sourdough Blondies Recipe (2024)

The best sourdough blondies recipe, complete with crackly top and a fudgy, sweet centre. Brimming with white chocolate chips, these sourdough blondies are made extra special with the addition of sourdough starter. I just know it's going to be one of your favorite recipes.

These sourdough blondies are like the perfect cross between chocolate chip cookies and sourdough brownies. They are the ultimate dessert bar and have become one of my absolute favorite things (I'm definitely a sweet tooth!).

If you love sourdough discard desserts, then you have to try these sourdough banana fritters, sourdough elephant ears and sourdough carrot cake muffins.

Why You'll Love This Recipe!

Perfect Gooey Blondie- You'll love these perfect gooey blondies, with the classic flavors of brown sugar and white chocolate chips that get caramelised as they bake. Is there anything better?

Cheap & Cheerful Sourdough Dessert- These sourdough blondies use basic pantry ingredients to create something truly delicious. There's no need for large amounts of chocolate like a traditional brownie.

They Freeze Really Well - Sourdough Blondies freeze really well and are great to have in the freezer for "dessert emergencies". I love to freeze as a whole block and then slice once thawed.

​Sourdough Discard or Active Sourdough Starter?

You can use either sourdough discard or active sourdough starter for this recipe. I've tested this recipe extensively and one thing I've discovered yields the best results is thicker sourdough starter or discard. So if you are using discard, make sure it's not too runny and sour as it will create an unpleasant sourness in these blondies, rather than a subtle tang.

Sourdough discard is the same as sourdough starter, it's just the unfed portion you remove from the jar before you feed it, so using either one is perfectly fine. You can find more definitions on all things sourdough in this sourdough glossary.

Using your sourdough discard is a great way to create less waste and ensure you're using every last bit of sourdough magic in your jar.

How To Make Sourdough Blondies

These sourdough blondies, or sourdough discard blondies, are super easy to make. The most difficult thing you'll need to do is whisk 2 egg whites until they form stiff peaks. The rest is relatively easy!

You'll just need a mixing bowl and a fork or spatula. No fancy equipment.

Preheat your oven to 350F (175C) and line a 9 x 9 inch square pan with parchment paper (you can butter and flour the pan if you prefer).

In a large bowl, whisk together the egg whites until stiff peaks form. Set aside while you assemble the other ingredients (you can of course do this in a stand mixer or with an electric hand mixer if you prefer).

Whisk together the melted butter and brown sugar (I've just used a fork for this step). It looks a bit like lumpy caramel.

Now add the egg yolks, vanilla and molasses (if you are using it) to the brown sugar and butter and whisk until combined.

Now add the all purpose flour, sourdough starter, baking powder, baking soda, salt and white chocolate chips. Stir until they are just combined (don't over mix).

Now gently fold in the egg whites until just combined (I use a small rubber spatula for this step).

Pour the sourdough blondie batter into the prepared pan and place into the oven. It's quite a thick mixture so you'll need to spread it out evenly.

Bake for 25 minutes at 350F (175C) until golden brown (insert a skewer into the blondies to see if it comes out clean).

Allow the blondies to cool in the tin before cutting into squares to serve.

What If I Don't Have Dark Brown Sugar?

This recipe calls for 220g of dark brown sugar to ensure you get the sweet butterscotch flavor blondies are renouned for. If you don't have dark brown sugar, you can use light brown sugar and add 20g of molasses to make up for the flavor.

If you really love those deep caramel flavors, you can use dark brown sugar and molasses. YUM!

​Flavor Additions for Sourdough Blondies

I love adding white chocolate chips to these sourdough blondies, but there's no limit to the ingredients or flavor additions that you can add to these gooey sourdough discard blondies. Here are a few ideas:

• Chocolate Chunk Blondies - add 100g of chopped semi-sweet chocolate for the ultimate caramel chocolate indulgence.
  
• Walnuts or Pecans - chop up 100g of your favorite nuts for a crunchy addition to these sourdough discard blondies.
  
• Butterscotch Chips - add 100g of butterscotch chips for an extra big hit of butterscotch sweetness.
  
• Brown Butter Blondies - Brown and cool your butter before making these sourdough blondies.
  
• Flaked Sea Salt - sprinkle a little flaky sea salt on top of the sourdough blondies before baking. The addition of flaky sea salt is a fun little twist on this classic sourdough dessert.

How To Store + Freeze

These sourdough blondies will keep in an airtight container for 3 days.

You can easily freeze this sourdough dessert. You can freeze the blondies as a whole, so don't cut them once baked, simply wrap in parchment paper and then foil and freeze for up to 3 months.

To freeze individual portions, cut into squares and then wrap each piece in parchment paper and then foil.

Allow to thaw at room temperature before enjoying.