Fudgy Sourdough Brownies

4.95 from 20 votes
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These aren’t your average brownies. They’re rich, fudgy, and secretly packed with sourdough discard, which adds an incredible depth of flavor and makes for an ultra-moist, deeply chocolatey bite. If you’ve never tried Sourdough Brownies before, you’re in for a treat—just like my Chocolate Sourdough Cupcakes, the discard brings amazing texture and moisture.

Made with dark cocoa and high-quality chocolate, these brownies bake up with gooey centers and a glossy layer of chocolate icing on top. They’re delicious at room temperature, but I actually love them chilled—just like I do with my sourdough chocolate chip cookie bars. I keep a stash in the freezer for late-night cravings, and trust me, they never last long.

A stack of three sourdough brownies on a plate with a bite taken out of them.

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Why You’ll Love Sourdough Brownies

Sourdough Discard Tip: I keep a jar in my fridge that I continually add sourdough discard to. Discard is a by-product of your sourdough starter and there is no reason to throw it away. Instead, use it in incredible sourdough discard recipes where it adds moisture and great flavor. Use older, more tangy discard in savory recipes like these Sourdough Discard Butter Crackers and young/fresh discard in sweeter recipes like my favorite Chocolate Sourdough Crinkle Cookies.

Important Ingredients

Ingredients are in small containers on a countertop and include brownie frosting, cocoa powder, brown sugar, chocolate, sugar, sourdough discard, vanilla, eggs, butter, flour, baking powder, and salt.
  • Sourdough Discard Use sourdough discard or active sourdough starter. 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 (fed equal weights of flour and water).
  • Flour: I recommend using all-purpose flour in this recipe. I think a soft whole wheat flour could also work well, but I haven’t tried it yet – let me know if you do!
  • Eggs: This recipe relies on creaming the egg and sugar together until light and fluffy – it’s where the brownies get their rich texture and height.
  • Chocolate  A good-quality dark or semi-sweet chocolate bar or good-quality chocolate chips bring deep chocolate flavor to these brownies. Chocolate chips are a little less stable, but I’ve found semi-sweet or bittersweet chocolate chips to work well in this recipe.
  • Cocoa Powder  A dark/dutch processed cocoa powder makes these fudgy brownies extra chocolately.

See the recipe card for full information on ingredients and quantities

Substitutions

  • Cocoa Powder: You can substitute regular cocoa powder instead of dutch processed cocoa powder, but the flavor won’t be quite as deep/rich.
  • Nuts: While this recipe doesn’t include them, you could add nuts to these brownies or sprinkle them on top of the frosting if you are looking for a nutty crunch on top.
  • Unsalted Butter: Salted butter can be substituted. If you are sensitive to salt, decrease the salt in the recipe to 1/4 tsp if substituting salted butter.
  • Frosting: The frosting is so simple and adds even more chocolatey goodness to these brownies, but you can leave it off completely or top with any favorite frosting. Add sprinkles, chopped nuts or mini mnms to the top of these brownies for a little flair.

How to Make Fudgy Sourdough Brownies

Mix The Batter

A liquid measuring cup contains a chocolate mixture with a spoon sticking out of it.

Step 1: Add the chopped chocolate (or semi-sweet chocolate chips), butter and cocoa powder to a liquid measuring cup. Microwave in 30 second increments until the chocolate is melted and the mixture is stirred smooth. Alternatively, melt chocolate mixture in a saucepan on the stove. Set aside until cool.

Three bowls contain chocolate, dry ingredients, and wet ingredients, respectively.

Step 2: Combine the brown sugar, granulated sugar and eggs in a medium bowl using a hand mixer or stand mixer for a few minutes until light and fluffy. Add the vanilla extract and the sourdough discard and mix until completely combined.

A hand mixer sits next to a bowl containing a chocolate mixture.

Step 3: Pour the cooled, melted chocolate mixture from the liquid measuring cup into the sugar/egg mixture and mix until completely combined.

A spatula sits in a mixing bowl filled with brownie batter.

Step 4: Add the flour, baking powder and salt to a small bowl and fluff together with a fork. Use a wooden spoon or spatula to fold the dry mixture into the chocolate batter. Gently stir until combined.

Sour Brownies? 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.

Prepare the Pan

A spatula holds brownie batter over a mixing bowl filled with the remaining batter.

Step 5: Line a pan with parchment paper. This will help prevent your brownies from sticking to the pan.

A square baking pan is lined with parchment paper and filled with brownie batter.

Step 6: Spread the brownie mixture into the parchment-lined 8×8 metal baking dish. This

This recipe makes thick sourdough brownies. If you prefer a thinner brownie, you may want to use a 9 by 9-inch pan instead.

Bake & Frost

A baked square pan of brownies sits on a countertop.

Step 7: Preheat oven to 350ºF and bake brownies for 50-55 minutes. 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. Let cool in the pan.

A close up shot shows an uncut pan of brownies frosted with chocolate frosting.

Step 8: After allowing the brownies to cool, remove from the pan and mix melted butter, cocoa powder, vanilla extract, milk, powdered sugar, and a pinch of salt until smooth. Spread frosting on top of the brownies.

Sourdough brownies on a piece of parchment paper on a table.

How to Store Leftovers

Wrap individual brownies in parchment and store in a freezer bag for a quick dessert fix. They last 1-2 months in the freezer. Let them thaw at room temp for 30 minutes—or eat them cold like I do!

Amy’s Recipe Tip

For the best flavor, use good quality semi-sweet or bittersweet chocolate—milk chocolate doesn’t hold up as well in these brownies. You can use chocolate chips or melt your favorite 8 oz chocolate bar. And don’t skip on the cocoa powder! A dark or Dutch-processed cocoa gives these brownies their rich, intense chocolate flavor, so choose a good one for the best results.

Frequently Asked Questions

Why do you add sourdough discard to brownies?

I find that sourdough discard adds moisture and flavor to recipes, plus there are great health benefits to sourdough because of the fermentation. If you use “newer” discard, these brownies won’t have a very pronounced tangy flavor.

Can I add nuts to these brownies?

Yes. Add about 3/4 to 1 cup chopped nuts (pecans or walnuts would be my pick) 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 dutch processed?

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

Can I use a glass pan to make these brownies?

I prefer using a metal baking pan for brownies because it bakes more evenly. You can use glass but be aware that glass holds heat longer – so brownies may tend to over-bake.

A stack of sourdough brownies on a plate.

Chocolate Sourdough Recipes

If you tried these Sourdough Brownies or any other recipe on my website leave a 🌟 star rating and let me know how it went in the comments below. Happy Baking!

A stack of three sourdough brownies on a plate with a bite taken out of them.
4.95 from 20 votes

Fudgy Sourdough Brownies

These sourdough brownies check every box: rich chocolate flavor, a gooey center, and a sweet icing on top. They're easy to make, freezer-friendly, and the perfect way to use up sourdough discard. Your whole family will love them!
Prep: 20 minutes
Cook: 55 minutes
Total: 1 hour 15 minutes
Servings: 16 brownies

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Ingredients 

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
  • 6 grams vanilla extract, about 2 teaspoons
  • 120 grams sourdough discard, 100% hydration, see recipe notes, about 1/2 cup
  • 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
  • pinch of salt, to taste

Instructions 

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, powdered sugar, and a pinch of salt until smooth. Spread on the lukewarm or cooled brownies. Enjoy!

Notes

This recipe makes a thick brownie. If you want thinner brownies use a 9 by 9 baking pan instead.
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 semi-sweet or dark chocolate bar. Most chocolate chips will work, but can be a little less stable. I’ve found semi-sweet or bittersweet chocolate chips to work well in this recipe.

Nutrition

Calories: 305kcal, Carbohydrates: 44g, Protein: 3g, Fat: 15g, Saturated Fat: 9g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 4g, Trans Fat: 0.3g, Cholesterol: 46mg, Sodium: 127mg, Potassium: 135mg, Fiber: 2g, Sugar: 32g, Vitamin A: 299IU, Calcium: 33mg, Iron: 2mg

Nutrition information is automatically calculated, so should only be used as an approximation.

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About Amy Coyne

Hi! I'm Amy. Sourdough lover and Kentucky based mama, sharing my best recipes and tips, one bake at a time. So glad you're here!

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86 Comments

  1. Deborah L Abrams says:

    Hi Amy,

    I am about to try this recipe, but have never made sourdough discard before. Can you please tell me how to do it?

    Thank you,
    Deb Abrams

    1. Amy says:

      Sourdough discard is just sourdough starter that needs to be fed and has already gone through a fermentation cycle. If you have sourdough starter you can let it sit or just substitute active sourdough starter for the discard in this recipe.

  2. Lena Madden says:

    These brownies were very tall! I weighed all ingredients. I think they’d be perfect baked in a 9×9 instead of 8×8

    1. Amy says:

      Thanks for sharing! They are a taller brownie and you could definitely bake them in a 9 by 9 pan if you wanted to.

  3. Alyssa says:

    5 stars
    Just like every recipe I have tried from Amy, these were amazing! Followed the recipe exactly and they turned out great!

    1. Amy says:

      So glad you loved these brownies. They are one of my favorites!

  4. Katherine says:

    5 stars
    Easy to follow. Love the frosting.

    1. Amy says:

      So glad you loved these!

  5. Kathy K says:

    Oh my…these were unbelievable. I have never baked brownies from scratch but wanted to give these a try as I am new to baking with sourdough discard. My husband could not stop raving about them! I didn’t do the frosting as I thought it might be too rich, but I do believe the frosting would have been amazing. Thank you for creating this fantastic recipe!!!

    1. Amy says:

      So glad you loved these brownies!

    2. Carrie says:

      4 stars
      I followed the instructions to exact measurements and directions but, my chocolate after melted was smooth but very thick, so when I mixed in the sugar egg mix it became so thick similar to a paste. And then trying to add the flour was difficult because everything was so thick. Was the batter suppose to be thick like that? What was the problem? I added a splash of milk so I could mix the batter. Baked as directed. They are the puffy. Still can’t wait to see what they are like when they cool. Thank you for all your recipes.

      1. Amy says:

        Wash your chocolate cooked too long and it seized up – getting thick and grainy? You said it was smooth so I’m not sure. If your chocolate is too thick you can add a little bit of hot cream or fat (butter) to it and mix it together to try and get it to smooth out again. I hope they turned out for you!

  6. Cyndy says:

    Is the metal pan essential?

    1. Amy says:

      No. It just gives crispier edges and a more even bake.

  7. Sam says:

    5 stars
    Just made. Going to eat the whole pan tonight

    1. Amy says:

      So glad you loved these!

  8. Melissa T says:

    5 stars
    Made these with my son on a snow day. I always use boxed brownie mix, because homemade never quite tastes as good. But this recipe has changed me! Goodbye box mixes. Hello sourdough goodness!! Thanks!

    1. Amy says:

      Awww…so glad you love these! Thanks so much for sharing.

  9. Justine says:

    Can these be made with a cold ferment option?

    1. Amy says:

      I think that would work well. Stick the batter in the refrigerator overnight or up to 24 hours.

  10. Sheila Daino says:

    Haven’t tried yet, but I see that it says to use a metal pan. I only have glass baking pans. I’ve only seen a couple of recipes that specifically call for a metal pan. Is there a difference, do I need to buy a metal pan for the recipes that call for one?

    1. Amy says:

      Metal bakes more evenly, so I typically prefer it for baked goods. I like glass for cobblers or things that hold heat for a longer time. If you use glass it will be okay, but may need a little longer to bake and I would line the pan with parchment so it’s easy to remove and they don’t overbake.