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Fudgy Sourdough Brownies

The perfect fudgy brownie with a crackly top is made even better with a dash of sourdough discard. Can a brownie be both fudgy and airy at the same time? Yep!

a stack of sourdough brownies on a white plate

A brownie can be both fudgy and airy if you add a cup of sourdough discard to the batter. These brownies are nice and rich, but with a surprisingly light crumb thanks to a little lift from the natural yeast in the sourdough starter.

But wait, there’s more…

The discard also enhances the flavor of the brownie. There’s a slight background tang that somehow makes the chocolate flavor even more chocolatey. It’s so, so good.

If you don’t have one, check out my post to learn How to Make a Sourdough Starter. Then check out my system to Feed and Maintain Sourdough Starter.

Scroll through the step by step photos to see how to make fudgy Sourdough Brownies:

showing how to mix sourdough brownie batter
Add the eggs and stir vigorously to incorporate air into the batter. This helps form the crackly crust. Fold in the sourdough discard.
showing how to add flour to sourdough brownie batter
Fold in the discard until almost combined, then fold in the flour.
sourdough brownies before and after baking.
Line the pan with parchment to make it easy to lift the brownies out of the pan

Tips for making and storing Sourdough Brownies:

  • The recipe can be halved and baked in an 8″ or 9″ square pan.
  • Unfed sourdough starter will add a tangy flavor to the batter. I got great results with a starter that had been in the refrigerator, unfed, for about a week.
  • Butter the pan and line with parchment paper. This not only prevents sticking, it makes it much easier to lift the brownies out of the pan.
  • Stirring the batter vigorously after adding the eggs will incorporate air into the batter. This will help form a crust on the top of the brownies. If you prefer a soft top on your brownies, you can skip that step.
  • Cool the brownies in the pan then use the parchment to transfer them to a cutting board.
  • To appreciate the subtle tangy flavor, I prefer to serve these spectacular brownies without any frosting
  • The Brownies will keep at room temperature for several days.
  • Leftover brownies can be frozen. Layer them with parchment paper or plastic wrap to prevent them from sticking together. They’re delicious straight from the freezer or defrosted.

You might like these other fabulous brownie recipes: Classic Fudgy Brownies, Habanero Brownies, Chocolate Cherry Brownies, Malted Milk Brownies, Roasted Beet Brownies, and White Chocolate Raspberry Brownies.

You might also like these recipes for the brownies’ cousin, Butterscotch Ripple Blondies and Malted Milk Blondies

I know you hate to throw away that sourdough discard. Check out these recipes that use sourdough discard.

Since you’ve got your starter fed, peruse the entire list of My Best Sourdough Recipes. Have fun!

a stack of sourdough brownies on a white plate
a hand holding a bite of a sourdough brownie

If you love this recipe as much as I do, I’d really appreciate a 5-star review.

a stack of sourdough brownies

Fudgy Sourdough Brownies

Yield: 24 brownies
Prep Time: 30 minutes
Cook Time: 20 minutes
Total Time: 50 minutes

The perfect fudgy brownie with a crusty top is made even better with a cup of sourdough discard.


  • 9 ounces bittersweet chocolate (252g) chopped
  • 2 sticks (8 ounces, 224g) unsalted butter, cut into 1" chunks
  • 1 cup (8 oz, 224g) granulated sugar
  • 1/2 cup (4 oz, 112g) brown sugar
  • 1/2 teaspoon salt
  • 1 tablespoon vanilla extract
  • 3 large eggs
  • 1 cup (8 oz, 224g) sourdough discard (100% hydration)
  • 1/2 cup (2.5 oz, 70g) all purpose flour


  1. Preheat the oven to 350°F. Butter a 13"x9" inch baking pan. Line the pan in one direction with parchment paper.
  2. Combine the chopped chocolate and the butter in a microwave safe bowl. Microwave for 1 minute, stir to combine. Microwave in 30 second increments (stirring between) until all the chocolate is melted.
  3. Add the brown sugar, granulated sugar, salt and vanilla, stir to combine. Add the eggs, stir until combined then stir vigorously for 30 seconds.
  4. Fold in the sourdough discard. Add the flour and stir just until combined. Spread the batter evenly into the prepared pan.
  5. Bake until the brownies puff up a bit and a toothpick inserted in the center comes out with a few moist crumbs (30 minutes).
  6. Cool in the pan to room temperature then refrigerate until the brownies are firm. Use the parchment paper to lift the brownies out of the pan onto a cutting board.
  7. Cut into 24 or 32 portions.

Did you make this recipe?

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Janet Pauli

Wednesday 23rd of December 2020

Hi Eileen. I just made these decadent brownies and I have a question. Why do you put the pan in the refrigerator? I was curious, so I took a little taste before going in the fridge. They were light and almost cakey (if that's a word). It was delicious. However, my policy with recipes is that I make it according to the directions the first time and then I make changes after that. They came out of the fridge very dense and fudgy. Have you ever made them and not put the pan into the fridge? The men in my family will love the dense chocolate but I would rather have the lighter density. I'm just curious if they would stay light without the cold.

Eileen Gray

Wednesday 23rd of December 2020

I refrigerate them mostly to get them firm enough to lift out of the pan. Otherwise, they might crack apart as they are lifted out of the pan.


Saturday 14th of November 2020


I halved the recipe but when i cut during cooled down the bottom is still wet.. what went wrong? My toothpick came out clean and top was crispy...

Eileen Gray

Saturday 14th of November 2020

What type of pan did you use? Do you have an oven thermometer to check for accuracy. Also, if you don't mix the batter evenly you might get the dense stuff at the bottom where the eggs aren't completely mixed in.

Allyson R.

Monday 26th of October 2020

Can I substitute an oil for the butter?

Eileen Gray

Monday 26th of October 2020

I think that would work. I can't say if the texture of the brownie will change much since I haven't tried it. Because butter is firm at room temp and oil is liquid at room temp, the brownies may be a bit mushy if you use a full cup of oil to replace the butter. I would try using 3/4 cup of oil and see how that works.


Tuesday 29th of September 2020

Love your recipes! Can I make the sour dough brownies using a box mix? Love Ghiradelli brownie box mix but want to see if I can add sour dough .

Eileen Gray

Tuesday 29th of September 2020

I honestly have no idea since I don't use box mixes. But I can't imagine it wouldn't work. Brownies are pretty forgiving since they naturally have a soft structure. All I can say is to give it a try and see what happens.


Saturday 26th of September 2020

I normally make bite-sized Nutella brownies for all of the football gatherings we host or attend. But since I received a gift starter a few weeks ago, I really wanted to try out some of your discard recipes because I hated throwing it out when I fed the starter, and I just don't let myself bake as often as I'd l. My husband was quite upset with me until he tasted these. These.Are. Amazing! Flavor was so nice without being too overly sweet like some brownies can be. Definitely in the rotation! Thank you so much for this recipe.