Vegan Sourdough Brownies

These vegan sourdough discard brownies are a delicious, fudgy vegan variation of my classic sourdough discard brownie recipe. This recipe is completely egg-free and dairy-free, making it perfect for people with dairy or egg allergies and vegans alike. You will love the rich chocolate flavor of these brownies that comes from both cocoa powder and melted chocolate. 

I crafted this recipe because I tried making my original sourdough brownie recipe by simply substituting vegan butter and egg replacers. It was a total fail! Brownies are a tricky recipe to get right and substituting vegan ingredients for the eggs and butter alters the chemistry of the brownies too much. I made several tweaks to my original recipe to perfect this vegan brownie recipe and I think you are going to love it.

There is a wooden cutting board that has a square of vegan sourdough brownies and parchment sitting on top. The brownies have been cut into 16 squares. There are also a few white flowers scattered around the brownies.


Fats: Vegan butter, cocoa powder, and melted chocolate all contribute to the fat content of this recipe. Vegan butters are typically oil based and result in brownies that are oily if you try to substitute it for regular butter. This is why I do not recommend trying to make a regular brownie recipe vegan. It’s better to find a recipe (like this one) that already adjusts the ingredients to compensate for their different chemistries. 

Flour: use regular all-purpose flour for this recipe. If you want to add some whole wheat flour, you can substitute 1/4 cup of whole wheat flour for the regular flour. I wouldn’t add more than this or it will make your brownies dry. 


Sourdough Discard: You can use either active sourdough starter, or unfed starter in this recipe. Because there is no rest time before baking, active starter doesn’t have time to act as a leavening agent. 

Whether you use active starter or sourdough starter discard will affect the taste of these brownies. Sourdough discard usually has a more sour taste compared to active starter. This is because sourdough discard has has used up all its food and fermented longer than the active starter. If you don’t want a strong tangy taste in your brownies, you are better off using active starter or pouring off the hooch on your starter. 

Sugar: This recipe contains only granulated sugar (aka white sugar). Brown sugar is often used in baked goods because it has a richer flavor and adds moisture, but with the sourdough starter and vegan egg replacer, these brownies are moist enough. 

Vegan Egg Replacer: This recipe is special in that it uses aquafaba as the vegan egg replacer. Aquafaba literally translates to “bean water,”  and that’s exactly what it is. Aquafaba is the water that beans sit in. You can make it yourself by pouring the liquid off of cooked beans, or by using a can of garbanzo beans (aka chickpeas). Simply pour out the liquid to use in this recipe and save the beans for eating later. 

Open can of chickpeas and aquafaba
Mesh strainer being used to strain aquafaba from garbanzo beans  into a white bowl.

Although seemingly strange, aquafaba works well as an egg replacer because it has proteins that allow it to thicken and whip up similar to whipped egg whites. It can be used to make vegan meringues, macarons, and mousses. We use aquafaba in this recipe to lighten the batter slightly and act as a binder. 

Vanilla Extract 

Finishing Touches: Extra chocolate chips are mixed directly into the brownie batter so you get an extra rich chocolate experience with every bite.

How to Make Sourdough Brownies with Discard

Step 1: Preheat the Oven and Prep the Pan

Prepare a 9 x9 inch metal baking pan. I highly recommend using a metal pan rather than a glass pan. Glass pans take longer to heat up in the oven but then hold their temperature better. This results in the edges getting over-cooked, and an overall longer bake time. 

Spray the baking pan with cooking spray, then line it with parchment paper. Leave a little bit longer on two sides of the pan so it goes up to the edge. This makes it much easier to remove the brownies when they are done baking. 

A 9x9 baking pan lined with parchment paper.

Step 2: Mix the Dry Ingredients

Whisk together the dry ingredients in a small bowl and set aside.

Step 3: Melt the Butter and Chocolate

Melt the butter and chocolate chips in the microwave for 30 seconds. Then, remove from the microwave and stir. Continue to microwave for 15 second intervals until the butter and chocolate is just melted and smooth. Make sure you stir between each interval.

yellow mixing bowl with chocolate chips and vegan butter.

Step 4: Add the Wet Ingredients

Add the sugar and vanilla and mix. Then, add the aquafaba. Use a whisk to beat the mixture until it gets slightly fluffy. This should take 2-3 minutes of continuous whisking. 

Add the sourdough starter and mix until smooth.

Melted butter, sugar, vanilla in a bowl with a whisk mixing in the sugar.
Yellow bowl with wet ingredients. The mixture looks slightly light and fluffy.
The mixture with the aquafaba should look slightly light and fluffy.

Step 5: Add the Dry Ingredients

Add the dry ingredients and stir with a rubber spatula until well incorporated and only small lumps of flour remain. It’s okay for the batter to be slightly lumpy. You don’t want to over-mix the batter!

Finally, stir in the reserved chocolate chips.

Step 6: Pour Into Pan 

Use a rubber spatula to evenly spread the batter in the prepared pan.  

brownie batter in mixing bowl with rubber spatula.
9x9 inch baking pan that is lined with parchment paper and contains the vegan sourdough brownie batter that is smoothed evenly in the pan.

Step 7: Bake

Bake the brownies for about 30-35 minutes. I recommend doing the “toothpick test” after 30 minutes. If you insert the toothpick into the batter and it is completely coated in raw batter, they need more time. I like to add another 5 minutes and check again. They brownies are done when the toothpick only has a few moist crumbs when removed from the brownies. They should also have a shiny layer on top that is slightly crinkly.

There are several squares of the vegan sourdough brownies on a wooden cutting board with some decorative flowers next to them.

How to Serve Vegan Sourdough Brownies

You can serve these brownies at room temperature or reheat them in the microwave for 10 seconds.

 I also love eating these with a scoop of vegan vanilla ice cream on top. You can add a drizzle of dairy-free hot fudge and caramel sauce and chopped toasted pecans for a turtle brownie sundae. It’s so good!

How to Store

Store these brownies in an airtight container or on a plate covered with plastic wrap. Try to eat these within 3-4 days for best results. To extend their freshness, store them in the refrigerator.  You can also freeze them ahead of time in a gallon freezer bag. 

Are Vegan Sourdough Brownies Healthy?

Vegan sourdough brownies are not any healthier than regular brownies because they still have a high amount of sugar and fat. That being said, brownies are usually thought of as a treat rather than a health food. 

I hope you enjoyed this sourdough discard recipe. These are some of the best brownies I’ve ever made and I hope you think so too. 

There is a wooden cutting board that has a square of vegan sourdough brownies and parchment sitting on top. The brownies have been cut into 16 squares. There are also a few white flowers scattered around the brownies.

Best Vegan Sourdough Brownies

These vegan brownies are fudge, rich and slightly tangy from the sourdough discard.
Prep Time 10 minutes
Cook Time 35 minutes
Total Time 45 minutes
Course Dessert
Cuisine American
Servings 16
Calories 172 kcal


  • 1 large bowl
  • 1 Whisk
  • 1 Small mixing bowl
  • 1 baking sheet
  • measuring cups
  • measuring spoons
  • Parchment Paper


  • 1 cup all-purpose flour
  • ½ cup cocoa powder
  • ½ teaspoon salt
  • 6 tablespoons vegan butter, melted
  • ½ cup semi-sweet chocolate chips + ⅓ cup for mixing into batter, set aside till end
  • cup granulated sugar
  • cup aquafaba liquid drained from a can of unsalted garbanzo beans
  • ½ teaspoon pure vanilla extract
  • ½ cup sourdough starter


  • Preheat the oven to 325℉
  • Prep a 9×9 inch baking pan. Spray with cooking spray, then line with parchment paper. Leave two ends a little longer so they go up to the edge of the pan.
  • In a small mixing bowl, whisk together the dry ingredients (all purpose flour, salt, and cocoa powder). Set aside.
  • In a medium microwave-safe mixing bowl, melt the vegan butter and chocolate chips in the microwave for 30 seconds. Continue to microwave at 15 second intervals until the mixture is just melted and smooth. Stir between each interval.
  • Remove from the microwave. Add the sugar and vanilla and whisk until combined.
  • Add the aquafaba and continue to whisk until the mixture becomes slightly lighter and fluffier (about 2-3 minutes of continuous whisking).
  • Whisk in the sourdough starter until smooth.
  • Slowly add in the dry ingredients and mix with a rubber spatula until there are no large clumps of flour (small lumps are okay). Do not over-mix.
  • Add the reserved chocolate chips and stir in until just combined.
  • Pour the mixture into the prepared baking sheet and smooth the top with a rubber spatula.
  • Bake for 30-35 minutes. A toothpick inserted should come out with only a few crumbs of moist batter. If the toothpick is coated in raw batter, return to the oven and bake at 5 minute intervals until done.
  • Allow to cool at least 15 minutes in pan before serving.


Calories: 172kcalCarbohydrates: 28gProtein: 2gFat: 7gSaturated Fat: 2gPolyunsaturated Fat: 1gMonounsaturated Fat: 3gTrans Fat: 1gCholesterol: 0.3mgSodium: 109mgPotassium: 83mgFiber: 2gSugar: 18gVitamin A: 3IUCalcium: 8mgIron: 1mg
Keyword Bars, Chocolate, Dairy-free, Egg-free, Sourdough, Sourdough Discard, Sweet Treats, Vegan
Tried this recipe?Let us know how it was!

If you loved these vegan sourdough aquafaba brownies, check out these other discard recipes:

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    1. I think it should be just fine. The texture could be slightly different from the fermentation but still delicious. This method is often used for batters like pancakes and other discard recipes so I think it would be great. I would love to hear how it goes if you try it!

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