Fudgy Sourdough Brownies

Sourdough brownies are the ultimate sweet treat with their rich chocolate flavor, fudgy center, and delectable frosting. What sets these fudgy sourdough brownies apart is the addition of sourdough discard, giving them a unique twist and enhancing their texture. I love eating these brownies chilled – you’ve got to try it! I keep a stash of them in my freezer for when the craving hits, they are so good. This sourdough brownie recipe will definitely satisfy your chocolate craving. Easy to whip up and oh so delicious, don’t wait any longer – make a batch of these incredible brownies today!

Ingredients in Fudgy Sourdough Brownies

  • Chocolate: Use a good quality chocolate bar or good quality chocolate chips. Chocolate chips are a little less stable, but I’ve found semi-sweet or bittersweet chocolate chips to work well in this recipe.
  • Unsalted Butter: I always bake with unsalted butter. It allows me to control the flavor in my baked goods — there is no standard for the amount of salt in salted butter, so you cannot predict how much salt has been added.
  • Cocoa Powder: Using a dark/dutch processed cocoa powder makes these fudgy brownies extra chocolately.
  • Sugar: A combination of granulated sugar and brown sugar brings the perfect balance of sweetness and chewiness to the brownies.
  • Sourdough Discard: You can use fresh, bubbly sourdough starter if you want. If you don’t mind a more pronounced sourdough flavor, you can use refrigerated discard from up to a week or two old.  I always use 100% hydration sourdough discard.
  • Eggs: Mixing eggs with the sugar turns the batter light and fluffy, forming the base of these delicious brownies.
  • Flour: I use all purpose flour in this recipe for best results.

Start with a Rich Chocolate Base

Fudgy sourdough brownies start with a rich chocolate base. Microwave together butter, chocolate and cocoa powder in a liquid measuring cup until melty – microwave in 30 second increments, stirring in between to keep the chocolate from getting too hot. Use a spoon to combine into a rich/thick liquid and then set aside to cool.

A note on the chocolate: I recommend a good quality semi-sweet or bittersweet chocolate. Milk chocolate doesn’t translate as well in these brownies. I’ve found that most brands of chocolate chips work in this recipe or grab your favorite 8oz chocolate bar to melt up. Also important is the cocoa powder. Definitely use a dark or dutched cocoa powder for best results. The intense chocolate flavor of these brownies comes from this chocolate base, so don’t skimp here–use good quality ingredients for best results.

Mix Together the Sourdough Brownie Base

Combining the eggs with the sugar is where the magic in the texture of these brownies starts. The way you combine the sugar and eggs combines air into the mixture and makes for extra fudgy brownie. Add the sugar and eggs to a bowl and mix with a handheld mixer for a couple of minutes until the brownie batter turns light and fluffy. Then add the vanilla extract and sourdough discard. Mix until combined. Mix in the cooled chocolate mixture and use the hand mixer to combine.

When adding sourdough discard to a recipe, if you want a pronounced sourdough flavor, use refrigerated discard up to a week or two old. If you don’t want a sour flavor, use fresh discard or bubbly sourdough starter.

Add Dry Ingredients

To a small bowl, mix together the flour, baking powder and salt. Fluff with a fork and add to the top of the brownie mixture. Using a spatula, combine until no dry streaks remain. If you don’t want to use a separate bowl (I don’t always), add the flour on top of the brownie mixture. Pour the salt and baking powder right on top of the flour and gently fluff. Then combine with a spatula, gently folding the dough together until it’s just combined.

Line the Pan with Parchment Paper

I always line my pan with parchment paper for brownies. It makes cleanup so much easier and it’s the easiest way to get beautiful brownie edges that don’t fall apart. Take an 8 by 8 metal pan and cut the corners out of parchment paper to fit the pan. Spread the brownie mixture into the parchment-lined pan.

Baking Sourdough Brownies

This sourdough brownie recipe makes thick brownies. They need about 50 minutes to bake completely, and even then the middle will be fudgy and gooey. If you want an even gooey-er brownie, it can bake for about 45 minutes or, for a firmer brownie give it 55-60 minutes. Every oven bakes a little bit differently, but the brownies should puff up and the middle should not sink back down once they are completely baked through.  Let the brownies cool completely before slicing into them so they can set up.

To Frost or Not to Frost?

I am team: ALWAYS FROST! I’m not going to turn down a brownie any day, but if I have the option to frost it, I’m going to! This is a super simple frosting and is definitely worth it. It requires little effort: Whisk together melted butter, cocoa powder, powdered sugar, vanilla extract and milk. That’s it! Melt the butter. Add the ingredients and use a whisk to whisk together. Spread over mostly-cooled brownies, and enjoy the most delicious brownies ever.

Frequently Asked Questions

How do I store leftover sourdough brownies?

I love freezing these brownies–and I eat them frozen or chilled straight from the freezer. If you don’t like a cold brownie, let it sit at room temperature for 30 minutes and enjoy. These are seriously so good no matter how you enjoy them…and kind of dangerous too!

I want to add nuts to my brownies. Can I add them to these?

Yes. Add them into the final mixed brownie batter if you want them in the brownies. Sprinkle them on top of the frosting if you are looking for a nutty crunch on top.

Can I substitute regular cocoa powder instead of dutched cocoa powder?

You can, but the flavor won’t be quite as deep/rich. If you can, I definitely recommend using a dutch process cocoa powder.

Fudgy Sourdough Brownies

Indulge in the ultimate sweet treat with these delicious fudgy sourdough brownies. Its rich flavor, fudgy center & delicious frosting will satisfy your chocolate craving.
5 from 3 votes
Prep Time 20 minutes
Cook Time 55 minutes
Total Time 1 hour 15 minutes
Course Dessert, Sweet Treats
Cuisine American
Servings 16 brownies


Sourdough Discard Brownies

  • 227 grams chocolate see recipe notes, about 8 oz
  • 113 grams unsalted butter about 8 Tablespoons
  • 35 grams cocoa powder see recipe notes, about 1/3 cup
  • 140 grams brown sugar about 2/3 cup
  • 150 grams granulated sugar about 2/3 cup
  • 2 large eggs about 100 grams
  • 120 grams sourdough discard, 100% hydration see recipe notes, about 1/2 cup
  • 6 grams vanilla extract about 2 teaspoons
  • 150 grams all purpose flour about 1 cup
  • 2 grams baking powder about 1/2 teaspoon
  • 4 grams salt about 1/2 teaspoon

Brownie Frosting

  • 55 grams unsalted butter, melted 1/4 cup
  • 25 grams cocoa powder see recipe notes, 1/4 cup
  • 3 grams vanilla extract about 1 teaspoon
  • 30 grams milk about 2 Tablespoons
  • 110 grams powdered sugar about 1 cup


Sourdough Discard Brownies

  • Preheat the oven to 350 degrees F.
  • To a liquid measuring cup, add the chopped chocolate (or semi-sweet chocolate chips), butter and cocoa powder. Microwave in 30 second increments until the chocolate is melted and the mixture is stirred smooth. Set aside to cool slightly. You can also do this on the stovetop if desired.
  • To a small bowl, add the brown sugar, white sugar and eggs. Using a hand mixer, mix the sugar and eggs together until light and fluffy. Add the vanilla extract and the sourdough discard and mix for a minute or two until completely combined.
  • Add the chocolate mixture to the sugar/egg mixture and mix again until completely mixed.
  • To a small bowl add the flour, baking powder and salt and fluff together with a fork. Add the flour mixture to the chocolate mixture and use a wooden spoon to combine completely.
  • Line an 8 by 8 metal pan with parchment paper. Pour the mixture in the pan and spread to the edges. Bake for about 50-55 minutes until set. The middle may still be a little gooey, but will set up as the brownies cool.
  • While the brownies cool, prepare the frosting. Mix together melted butter, cocoa powder, vanilla extract, milk and powdered sugar until smooth. Spread on the lukewarm or cooled brownies. Enjoy!


Sourdough Discard: You can use fresh, bubbly sourdough starter if you want. If you don’t mind a more pronounced sourdough flavor, you can use refrigerated discard from up to a week or two old.  I always use 100% hydration sourdough discard.
Dutch Processed Cocoa Powder: Using a dark/dutch processed cocoa powder gives these sourdough brownies a delicious chocolate flavor. You can use a regular cocoa powder, but the final result will not be quite as rich.
Chocolate: Use a good quality chocolate bar or good quality chocolate chips. Chocolate chips are a little less stable, but I’ve found semi-sweet or bittersweet chocolate chips to work well in this recipe.
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Recipe Rating


  1. 5 stars
    So yummy!! Thick, and chewy goodness! The icing just tops it all off!! 💯. Will definitely be making regularly!!

  2. 5 stars
    I’ve been making these brownies for a while now. They are the perfect brownie. Fudgy, slightly cakey but more fudgy. They are dangerously delicious!