If you're looking for brownies with crispy edges, fudgy centers, a shiny crackly top, and rich chocolate flavor, this one's for you. Sourdough discard adds a subtle tang that enhances the rich cocoa flavor, while a few simple techniques keep the texture chewy instead of cakey or underbaked. Made with just a bowl, a whisk, and a few pantry staples, the batter comes together quickly for brownies that taste better than a box mix without much extra effort.
This recipe was originally published on July 2022. I have since updated it with new photos and additional tips for success.
5-Star Review ★
My daughter says these are the best brownies she has ever had, and I bake a lot. They are very close to perfect!
Janet
If you're like me, you know sourdough discard is too precious to throw away. It's why I love sharing recipes like my sourdough discard chocolate cake and sourdough discard chocolate chip cookies but adding discard to brownies can be tricky. Sourdough discard adds extra moisture, which can turn brownies cakey instead of fudgy, and its tang can taste a little off if the brownies are underbaked.
Pro-Tips for the Fudgiest Sourdough Brownies
You guys know I love explaining the "why" behind a bake. After plenty of testing, I finally found the secret to getting that perfect crackly top and chewy center while still using your sourdough discard.
How to Get a Shiny, Crackly Crust
Grab your whisk and dissolve the sugar completely. I microwave the sugar with the butter. Since sugar dissolves in water (not fat), the moisture in the butter (combined with the water naturally found in sourdough discard) helps the sugar migrate to the surface as it bakes, forming that signature delicate crust.
Pro Tip: This technique is a game-changer for sourdough blondies, too.
Getting the Perfect Texture
Too much liquid is the enemy of a fudgy brownie. To balance the extra moisture from sourdough discard, I add a small amount of cornstarch. It helps bind excess water so the brownies stay dense and chewy instead of dry and cakey.
The "Secret" Ingredient
I've had the chance to work with the King Arthur Baking Company test kitchen on numerous occasions, so I tend to trust their recommendations. My fellow contributor, PJ Hamel, suggests adding chocolate chips to help create the glossy top.
It's thought that the soy lecithin acts as an emulsifier that helps reduce the separation of cocoa butter, cocoa solids, and sugar, allowing the mixture to form that thin, shiny, crackly, delicate meringue layer on top.
Ingredients
Granulated sugar: White sugar is the best choice for brownies since it doesn't contain as much moisture as other sugars. Organic cane sugar will work for this recipe, but do not try to use brown sugar or another type of sweetener (like maple syrup, honey or artificial sweeteners) since they have different chemical properties and moisture content.
Sourdough discard: You can use your sourdough discard or excess sourdough starter directly from the fridge. Add 28 grams of flour and 28 grams of water into your batter if you don't have any sourdough discard.
Cocoa powder: I used Dutch-processed cocoa powder, natural cocoa powder will work just as well for this recipe, but your brownies may turn out lighter in color.
All-purpose flour: Do not substitute whole wheat flour or cake flour, or it will ruin the texture of these brownies.
Chocolate chips: USE CHOCOLATE CHIPS not chocolate bars. This is extremely important since chocolate chips contain soy lecithin which contributes to getting a shiny crust. Milk chocolate or semi-sweet also work best since they have more sugar.
See recipe card for full ingredient amounts.
Step-by-step Instructions (with photos)
STEP 1: Melt the butter and sugar
Microwave sugar and butter together and whisk. Whisk in egg and egg yolks until the sugar looks completely dissolved. This step is pivotal for these brownies since hot butter and moisture from the egg whites and sourdough discard helps properly dissolve sugar, leading to a papery thin crackly crust.
STEP 2: Make the batter
Stir in the vegetable oil, cocoa powder. Whisk in sourdough discard until no traces remain or you may end up with gummy patches of sourdough in your brownies. Using a rubber spatula stir in the dry ingredients. Fold in the chocolate chips until evenly distributed.
STEP 3: Bake
Transfer the batter to a parchment-lined metal baking pan (8 by 8 inches). Bake the brownies at 325 F for 30 minutes. Do not over bake these brownies or they will taste chalky.
Notes from Hannah's Test Kitchen
- Both active sourdough starter and sourdough discard will work for this recipe. No starter? Just add 28 grams of flour and 28 grams of water to your batter.
- Use a metal pan. Baking brownies in a metal pan result in taller, thicker and chewier brownies compared to a glass or ceramic pan.
- Don't over bake your brownies. Over baking chocolate tends to dull its flavor, so if your brownies stay in the oven too long they will taste chalky and bland.
Make Ahead Instructions
- To Store: Slice and wrap individual pieces in plastic wrap, or wrap the entire tray tightly.
To Serve: Defrost at room temperature for a quick snack, or pop a slice in the microwave for a few seconds.
The Upgrade: Warm brownies and top with a dollop of vanilla ice cream = fudgy perfection.
Did this recipe rise to the occasion?
★★★★★
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Sourdough Brownie Recipe
Equipment
- 8 by 8 inch baking pan
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Ingredients
- 70 grams unsalted butter
- 250 grams granulated sugar
- 1 egg large
- 2 egg yolks
- 72 grams vegetable oil
- 75 grams cocoa powder Dutch-processed
- 56 grams sourdough discard
- 40 grams all-purpose flour
- ⅛ teaspoon baking soda
- 7 grams cornstarch
- 4 grams salt Morton's Kosher Salt
- 100 grams chocolate chips
- Pinch flaky sea salt optional
Click US Customary to view volume measurements
Instructions
- Prep: Preheat the oven to 325 F with the rack in the middle. Line an 8-by-8 baking pan with two pieces of parchment stacked perpendicular to each other, cut longer pieces for an overhang.
- Mix sugar and butter: Combine butter and sugar in a large mixing bowl (you'll be using this bowl for the entire recipe so choose an appropriate size). Microwave for 2 minutes, whisk until completely combined.70 grams unsalted butter, 250 grams granulated sugar
- Whisk in eggs: Let the mixture cool slightly to prevent your eggs from heating up too much and getting scrambled. Whisk in the egg and egg yolks until the sugar appears completely dissolved.1 egg, 2 egg yolks
- Add in cocoa powder and wet ingredients: Whisk in the cocoa powder and vegetable oil. Stir in the sourdough discard thoroughly until no traces remain.72 grams vegetable oil, 75 grams cocoa powder, 56 grams sourdough discard
- Fold in dry ingredients: Add the all-purpose flour, baking soda, cornstarch and salt. Use a rubber spatula to fold the ingredients in until no dry bits remain.40 grams all-purpose flour, ⅛ teaspoon baking soda, 7 grams cornstarch, 4 grams salt
- Add chocolate chips: Stir the chocolate chips into the batter until evenly distributed.100 grams chocolate chips
- Bake: Pour the batter into your prepared pan. Bake for 30 minutes or until the brownies are set and a toothpick inserted in the center comes out with moist crumbs attached. Transfer the pan to a wire rack to cool completely before slicing.
- Enjoy and store: Sprinkle flaky sea salt on top, if using. Slice the brownies into 9 to 16 squares. Store brownies in an airtight container at room temperature for up to 3 days.Pinch flaky sea salt
Tips
These recipes were developed and tested using grams for precise measurements. To increase your chances of success, I recommend investing in a kitchen scale. I've included rough volume estimates (in tablespoons and cups), but they might not be totally accurate.
Remember all ovens are unique, these recipes were tested in my oven which runs cooler than others. You might need to lower the temperature if your bake appears to be browning too quickly. Monitor your bake closely and make adjustments if needed.
Notes
Nutrition
I am not a nutritionist or dietitian, any nutrition information provided is an estimate.
Kylie says
These are sooooo good. One of the few brownies that are better cool rather than fresh from the oven, they don’t really “set” until they cool down. I love them topped with flaky salt. Such a rich chocolate flavor. I did half semisweet half bittersweet chocolate chips since it doesn’t specify. Thanks for a lovely recipe.
Hannah Dela Cruz says
Hi Kylie! So happy you loved the recipe. I totally agree with you that these are better once they've set and stay good even days later. I've heard other readers say they love them frozen. Glad you found something you loved.
Jenny says
I wish I could see what is meant by this:
Line an 8-by-8 baking pan with two pieces of parchment stacked perpendicular to each other, cut longer pieces for an overhang.
Hannah Dela Cruz says
Hi Jenny! Here's a website with helpful images for you: https://www.reynoldsbrands.com/tips-and-how-tos/how-make-parchment-sling
Bekah says
Could I turn this recipe into brownie cookies? These look soooo perfect!! Excited to make them either way:)
Hannah Dela Cruz says
Hi Bekah! Thank you! Unfortunately, I think the batter may be too thin and the cookie may spread too much.
Bing says
Hi! Is it ok to substitute natural dark cacao powder for dutch processed cocoa? Thanks! I’m excited to try your recipes 🙂
Hannah Dela Cruz says
Hi Bing - Natural cocoa powder is acidic while Dutch Cocoa powder is alkaline. Substituting will change the pH of the batter and will significantly change the texture of your brownies. Instead of being chewy and fudgy your brownies may become cakey and dry.
Margaret Casey says
Excellent. My kids and I looove them. They’re so rich and dense. The flavor is amazing.
Hannah Dela Cruz says
I'm so happy you love them!
Diane Gomberg says
I do love this recipe even with all of the special instructions that are needed. I made this for a social group I attend and they ate their fill and even absconded with the leftovers! LOL I do have one question though; the carbohydrate count of 25 grams per piece, is this for 9 pieces per pan or 16?
Thank you for your response.
Hannah Dela Cruz says
So glad you loved it! The nutrition info is 16 pieces per pan.
Diane Gomberg says
Thank you for the info.
Katie says
can you put this batter in muffin tins?
Hannah Dela Cruz says
I've never tried this personally but I don't see why not. If you wanted to try - be aware that I have never tested the recipe using muffin tins.
But you can always try. Bake them at 350 for 15 to 20 mins. Careful not to overbake or they may end up tasting chalky.
Good luck and let me know how it goes!
Linda says
These were, by far, the best brownies I’ve ever made! Super chocolatey! They were moist in the middle without that undercooked batter that you sometimes get. I put a rocky road topping on them and my family loved them! Will be my go to from now on! Thanks!
Hannah Dela Cruz says
This is what I love to hear! So glad your family loved the recipe.
Marion Castoire says
How delicious! This is the second time I've made it, and my daughter loves it. Since we're very careful with our sugar intake, I used Splenda, and it was delicious! This second time, we added instant coffee. OMG! Amazing! And the sourdough starter I used both times had chocolate in it. Incredible. 100% recommended! Thanks for sharing! ❤️
Hannah Dela Cruz says
So glad you loved it and the recipe worked with your substitutions.
Jewels says
WOW- the BEST brownie I have made in a very very long time. I used metric by weight in ingredients and followed the recipe as is using my discard. I baked it for 28 min instead of 30 as I really like a gooey brownie and it was perfect. My husband is in love with them! You really did get this PERFECT!!
Hannah Dela Cruz says
Thank you so much Jewels! I worked really hard to get this one right for you guys and I am so happy you're loving the recipe!
Nicole says
I've already made this recipe twice in one week. I experimented with discard I had in my fridge for 4 weeks, and everyone loved them! They didn't taste sour at all. In my oven they needed 40 minutes to bake, and I added 1 t of vanilla.
Hannah Dela Cruz says
So glad you loved it!
Sara says
Best sourdough brownies ever! We made a 1 1:2 batches and combined it all in 1 baking pan for thicker brownies
Mike Smith says
We use the version from your cookbook, very good. We live in the Philippines and have an abundance of bananas on our property. Always looking for ways to use the bananas, we sliced up a couple of cups worth and mixed into a double batch of the brownies. Came out lami kaayo.
Mike Smith
Hannah Dela Cruz says
So glad you are enjoying the book and recipes all the way in the Philippines!
Janet Moholland says
These brownies are easy to make and my daughter says they are the best brownies she has ever had. The only adjustment I make is, I add Vanilla extract and I double the batch and bake in a 9x13 pan. If you have sourdough, definitely try this recipe!
Hannah Dela Cruz says
so glad your daughter loves them!
Dani Shirey says
I have made these once before and I made them for a Super Bowl party this evening. I made a double batch, cooked them in my 9X13 cast iron baking dish, and added cinnamon chips instead of chocolate chips (we had them on hand) and these are AMAZING!!!! I also used dark chocolate instead of regular with olive oil. I love these so much because they are not overly sweet and have an amazing unique taste because of the discard. These are my go-to brownies now!
Hannah Dela Cruz says
So glad you loved the recipe, Dani! I love the changes you made and I'll have to try those myself!
Whitney says
These are currently in the oven and I am already drooling! This is my first ever sourdough recipe and even though I used rye starter, I’m still so excited to eat these! I used a mix of milk and dark chocolate chips since I don’t have a super sweet tooth and used olive oil as that was all I had. Also, can I just say how much I appreciate you listing the ingredients in each step of the recipe?? It’s a huge help not having to scroll back up to the listing. THANK YOU!! Happy I found your site and all of your amazing, thoughtfully put together recipes!
Hannah Dela Cruz says
I'm glad the recipe format helped and hope you enjoyed your brownies!
Kassidy says
Do you have a suggestion for an alternative to microwaving the sugar and butter? Would a double boiler work since we do not use the microwave to avoid the adverse health effects.
Hannah Dela Cruz says
You can melt the butter and pour it into the sugar while it is still hot.
Erica says
Overall this is a great recipe! I loved the texture! I personally have a whole wheat starter and it came out tasting a bit more sour than I’d hope. I’m wondering if the whole wheat is what brought out the sour flavor. Other than that it was great and I will definitely try again. If you have any suggestions please let me know.
Hannah Dela Cruz says
Whole wheat starters do have a tendency to be more acidic because of the presence of bran in the flour. This nutrient-dense food source encourages the growth of lactic acid bacteria which produces more lactic and acetic acid, contributing to the sour flavor and is only exacerbated by the acidity that is built up in discard that isn't regularly fed. I would try using freshly fed whole wheat starter if you want to decrease the sourness and see if that helps.
Hailey says
This worked really well! The texture was absolutely amazing. I will say- I used dark chocolate chips and the dark chocolate really does make the sour taste a little stronger from the starter. I would prob not use dark chocolate and use semi or milk chocolate to even out the bitter/sour taste. (My fault) but yes, these are great!
Hannah Dela Cruz says
Glad you loved it!