Homemade Vegan Sourdough Brownies

I never thought I’d find a way to use my sourdough discard that my kids would actually fight over, but here we are. These vegan brownies happened by accident one day when I had a cup of starter sitting on the counter and a serious chocolate craving.

Turns out, sourdough starter does something really nice to brownies—it gives them this slight tang that plays off the chocolate in a way regular brownies just don’t have. And because they’re vegan, you don’t need eggs or dairy butter, which means you can actually eat the batter without worry. Not that I’m saying you should, but I’m also not saying I didn’t.

What Kind of Sourdough Starter Should I Use?

Any active sourdough starter will work great for these brownies, whether it’s made with white flour, whole wheat, or even rye. The key is making sure your starter is fed and bubbly – you want it at its peak activity, which is usually about 4-8 hours after feeding. Don’t worry too much about the flavor profile of your starter affecting the brownies, since the chocolate and cocoa will be the dominant flavors. If your starter has been sitting in the fridge for a while, just feed it the night before and let it come to room temperature before using it in your recipe.

Options for Substitutions

These brownies are pretty adaptable, so here are some swaps you can make based on what you have:

• Sourdough starter: The sourdough starter is what makes these brownies special, giving them a slight tang and chewy texture. Don’t substitute this one – it’s the star of the recipe.
• Vegan butter: You can use coconut oil instead, but keep in mind it might add a subtle coconut flavor. Regular vegetable oil works too, though the texture will be slightly less rich.
• Aquafaba: If you don’t have aquafaba (the liquid from canned chickpeas), you can use 1/4 cup of unsweetened applesauce or mashed banana instead. The texture will be a bit more cake-like rather than fudgy.
• Chocolate chips: Any dairy-free chocolate chips work here – dark chocolate, semi-sweet, or even chopped vegan chocolate bars. You can also leave them out if you prefer a more classic brownie.
• All-purpose flour: Whole wheat flour can replace half the all-purpose flour for a nuttier taste, or use a 1:1 gluten-free flour blend if needed.
• Cocoa powder: Dutch-processed or natural cocoa both work fine. Just stick with unsweetened cocoa powder for the best results.

Watch Out for These Mistakes While Baking

The biggest mistake you can make with these brownies is overbaking them – since they’re made with sourdough starter and aquafaba instead of traditional eggs, they can dry out quickly, so pull them from the oven when a toothpick comes out with a few moist crumbs, not completely clean.

Another common error is not whisking the aquafaba long enough, as those 2-3 minutes of whisking are crucial for creating the light, airy texture that mimics eggs and gives your brownies their fudgy consistency.

Make sure your sourdough starter is at room temperature before adding it to the batter, because cold starter won’t mix in smoothly and can create lumps in your final product.

Finally, resist the urge to cut into these brownies right away – letting them cool completely in the pan helps them set properly and prevents them from falling apart when you slice them.

What to Serve With Vegan Sourdough Brownies?

These brownies are pretty rich and fudgy on their own, so I like keeping things simple with a scoop of vegan vanilla ice cream on top while they’re still warm. A cold glass of oat milk or almond milk is perfect for washing down the chocolate goodness, or you could go with a hot cup of coffee if you’re serving them as an afternoon treat. If you want to dress them up a bit, try adding some fresh raspberries or strawberries on the side – the tartness cuts through the sweetness really nicely. You can also dust them with a little powdered sugar or drizzle some melted vegan chocolate on top for extra decadence.

Storage Instructions

Store: Keep your brownies fresh by storing them in an airtight container at room temperature for up to 4 days. If you want them to last a bit longer, pop them in the fridge where they’ll stay good for about a week. They actually taste amazing cold straight from the fridge if you like a fudgier texture!

Freeze: These brownies freeze really well for up to 3 months. Cut them into individual squares and wrap each one in plastic wrap, then store them all together in a freezer bag. This way you can grab just one or two whenever a chocolate craving hits without thawing the whole batch.

Enjoy: To enjoy frozen brownies, just let them thaw at room temperature for about 30 minutes. If you’re impatient like me, you can microwave them for about 15-20 seconds for that fresh-baked warmth. They’re also delicious eaten straight from the freezer if you like a firmer, almost truffle-like texture.

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 1800-2000
• Protein: 18-24 g
• Fat: 70-80 g
• Carbohydrates: 270-290 g

Ingredients

For the dry mix:

• 1 1/4 cups all-purpose flour
• 2/3 cup unsweetened cocoa powder (sifted)
• 1/2 tsp salt
• 1/2 tsp instant espresso powder

For the batter:

• 7 tbsp vegan butter (Miyoko’s Creamery recommended)
• 1/2 cup vegan chocolate chips (melted and cooled)
• 1 1/4 cups granulated sugar
• 1/3 cup aquafaba (whipped until foamy)
• 1 tsp vanilla extract
• 1/2 cup active sourdough starter
• 1/4 cup vegan chocolate chips (reserved for mixing in)

Step 1: Prepare Pan and Preheat Oven

Preheat your oven to 325°F.

While the oven heats, line an 8×8 inch baking dish with parchment paper, allowing some overhang on the sides for easy removal later.

This setup means your brownies will be ready to go into the oven as soon as the batter is mixed.

Step 2: Combine Dry Ingredients

• 1 1/4 cups all-purpose flour
• 2/3 cup unsweetened cocoa powder
• 1/2 tsp salt
• 1/2 tsp instant espresso powder

In a medium bowl, whisk together the flour, sifted cocoa powder, salt, and instant espresso powder.

The espresso powder won’t make the brownies taste like coffee—instead, it deepens and intensifies the chocolate flavor.

Set this dry mixture aside while you work on the wet ingredients.

Step 3: Melt Butter and Chocolate, Build the Wet Base

• 7 tbsp vegan butter
• 1/2 cup vegan chocolate chips
• 1 1/4 cups granulated sugar
• 1 tsp vanilla extract

In a microwave-safe bowl, combine the vegan butter and 1/2 cup melted vegan chocolate chips.

Microwave in 30-second intervals, stirring between each, until completely smooth and melted—this takes about 1-2 minutes total.

Let the mixture cool slightly, then stir in the granulated sugar and vanilla extract until well combined.

This cooling step is important because it prevents the aquafaba from breaking down when you add it next.

Step 4: Whip Aquafaba and Create the Batter Base

• 1/3 cup aquafaba
• 1/2 cup active sourdough starter
• wet ingredient mixture from Step 3

Pour the aquafaba into a bowl and whisk it vigorously for 2-3 minutes until it becomes foamy with visible peaks—this aerates the batter and helps create lift and a fudgy texture in the brownies.

Gently fold the whipped aquafaba into the cooled chocolate mixture from Step 3 until just combined.

I find that using a sourdough starter in vegan baking really enhances the brownie’s depth, so next stir in the active sourdough starter until fully incorporated.

Step 5: Combine Wet and Dry Ingredients

• dry ingredient mixture from Step 2
• wet ingredient mixture from Step 4
• 1/4 cup vegan chocolate chips

Add the dry ingredient mixture from Step 2 to the wet batter from Step 4, folding gently with a spatula until just combined—don’t overmix, as this keeps the brownies tender.

Fold in the reserved 1/4 cup vegan chocolate chips, distributing them evenly throughout the batter.

Step 6: Bake and Cool

• batter from Step 5
• parchment-lined pan from Step 1

Pour the batter into your prepared pan from Step 1, spreading it evenly.

Bake at 325°F for 30-35 minutes—the brownies are done when a toothpick inserted in the center comes out with just a few moist crumbs (not wet batter).

Let the brownies cool in the pan for 15 minutes, then lift out using the parchment paper overhang and transfer to a wire rack to cool completely before slicing.

I find that this cooling time in the pan helps them set properly without becoming too dry.

Homemade Vegan Sourdough Brownies

Delicious Homemade Vegan Sourdough Brownies recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 15 minutes mins

Cook Time 30 minutes mins

Total Time 45 minutes mins

Servings 16 pieces

Calories 1900 kcal

Ingredients

  

For the dry mix::

• 1 1/4 cups all-purpose flour
• 2/3 cup unsweetened cocoa powder (sifted)
• 1/2 tsp salt
• 1/2 tsp instant espresso powder

For the batter::

• 7 tbsp vegan butter (Miyoko's Creamery recommended)
• 1/2 cup vegan chocolate chips (melted and cooled)
• 1 1/4 cups granulated sugar
• 1/3 cup aquafaba (whipped until foamy)
• 1 tsp vanilla extract
• 1/2 cup active sourdough starter
• 1/4 cup vegan chocolate chips (reserved for mixing in)

Instructions

 

• Preheat your oven to 325°F. While the oven heats, line an 8x8 inch baking dish with parchment paper, allowing some overhang on the sides for easy removal later. This setup means your brownies will be ready to go into the oven as soon as the batter is mixed.
• In a medium bowl, whisk together the flour, sifted cocoa powder, salt, and instant espresso powder. The espresso powder won't make the brownies taste like coffee—instead, it deepens and intensifies the chocolate flavor. Set this dry mixture aside while you work on the wet ingredients.
• In a microwave-safe bowl, combine the vegan butter and 1/2 cup melted vegan chocolate chips. Microwave in 30-second intervals, stirring between each, until completely smooth and melted—this takes about 1-2 minutes total. Let the mixture cool slightly, then stir in the granulated sugar and vanilla extract until well combined. This cooling step is important because it prevents the aquafaba from breaking down when you add it next.
• Pour the aquafaba into a bowl and whisk it vigorously for 2-3 minutes until it becomes foamy with visible peaks—this aerates the batter and helps create lift and a fudgy texture in the brownies. Gently fold the whipped aquafaba into the cooled chocolate mixture from Step 3 until just combined. I find that using a sourdough starter in vegan baking really enhances the brownie's depth, so next stir in the active sourdough starter until fully incorporated.
• Add the dry ingredient mixture from Step 2 to the wet batter from Step 4, folding gently with a spatula until just combined—don't overmix, as this keeps the brownies tender. Fold in the reserved 1/4 cup vegan chocolate chips, distributing them evenly throughout the batter.
• Pour the batter into your prepared pan from Step 1, spreading it evenly. Bake at 325°F for 30-35 minutes—the brownies are done when a toothpick inserted in the center comes out with just a few moist crumbs (not wet batter). Let the brownies cool in the pan for 15 minutes, then lift out using the parchment paper overhang and transfer to a wire rack to cool completely before slicing. I find that this cooling time in the pan helps them set properly without becoming too dry.