Do you have extra sourdough starter in the fridge and you’re not sure what to do with it? These soft, chewy sourdough chocolate brownies are a fantastic way to turn discard into something delicious. If you want to branch out from classic sourdough bread, these brownies offer an easy, tasty option that showcases the starter’s subtle tang while delivering rich, fudgy chocolate flavor. The starter contributes a bit of acidity and depth along with fiber and beneficial bacteria when used in baking, and this simple recipe is a great introduction for sourdough beginners who want a non-bread project.
Why You’ll Love This Recipe
Soft and chewy texture. If you prefer brownies that are tender and slightly gooey rather than cakey, these are ideal.
Deep chocolate flavor. A mix of melted chocolate chips and cocoa powder creates a rich, fudgy base that satisfies chocolate cravings.
Great for using sourdough discard. Instead of throwing away excess starter, fold it into brownie batter and enjoy a small tang that enhances the chocolate.
Freezer-friendly. These brownies freeze well, so you can bake ahead for guests or keep a supply on hand for quick desserts.
Ingredients
(A printable version of this recipe is helpful—see the recipe card or copy the list below.)
- 1/2 cup unsalted butter
- 1 1/2 cups semi-sweet chocolate chips
- 1/2 cup cocoa powder (any kind)
- 2 teaspoons vanilla extract
- 2 large eggs
- 1 egg yolk
- 1 cup granulated sugar
- 1/2 cup brown sugar
- 125 grams sourdough starter discard (weigh on a food scale)
- 1 cup all-purpose flour
- 1 teaspoon salt
Instructions for Sourdough Chocolate Brownies
- Preheat the oven to 350°F (175°C). Line a 9-inch square baking pan with parchment paper, creating a sling so you can lift the brownies out easily once cooled.
- In a microwave-safe bowl, combine the butter and chocolate chips. Microwave in short bursts, stirring between intervals, until fully melted and smooth (about 1 1/2–2 minutes total, depending on your microwave). Stir in the cocoa powder and vanilla, then set the chocolate mixture aside to cool slightly.
- In the bowl of a stand mixer (or using a hand mixer), beat the two eggs, the extra egg yolk, and both sugars on medium-high speed until the mixture is light, frothy, and smooth—around 7–10 minutes. This aeration helps create a shiny, slightly crackly top.
- With the mixer on low, pour in the cooled melted chocolate and the sourdough discard. Mix until just combined and uniform in color.
- Add the flour and salt all at once, then fold or mix on low until just combined. The batter will be thick—this is expected. Spoon large dollops of batter into the prepared pan and spread gently with a knife or offset spatula to an even layer.
- Bake at 350°F for 35–40 minutes, or until the top is set and begins to crack but the center remains fudgy. A toothpick inserted near the center may come out with a few moist crumbs; avoid baking until it’s completely dry.
- Cool the brownies completely in the pan, then lift them out using the parchment sling and transfer to a cutting board for slicing.
Tips & Tricks
- Let the brownies cool completely before removing them from the pan for clean slices.
- Create a cardstock template if you want perfectly square pieces—use it as a guide when cutting.
- Use a large, sharp knife heated under hot water (then dried) to make smooth cuts. Wipe and reheat the knife between slices for the best results.
- Don’t overbake. For chewy, fudgy brownies, err on the side of slightly underdone in the center; they will set as they cool.
How to Store Sourdough Chocolate Brownies
Once cooled, store brownies in an airtight container at room temperature or in the refrigerator for up to 4 days. To freeze, wrap portions tightly or place them in a freezer-safe container or zipper bag and store for up to 4 months. Thaw at room temperature before serving.
Recipe at a Glance
- Yield: about 16 brownies
- Prep time: 15 minutes
- Cook time: 35–40 minutes
- Total time: about 55 minutes
Other Brownie Ideas
- Butterscotch brownies—sweet and buttery variations add a different flavor profile.
- Quick classic brownies—easy scratch recipes that come together in minutes.
- Black bean brownies—use beans for a gluten-free, fudgy alternative.
Other Ways to Use Sourdough Discard
- Sourdough rhubarb muffins (or swap in other fruit) for tender breakfast treats.
- Honey oat sourdough sandwich bread—soft loaves perfect for sandwiches.
- Dutch oven sourdough bread for a traditional, crusty loaf.
- Sourdough chips or crackers—quick, savory snacks flavored with herbs and spices.
Tools That Make This Easier
A 9×9-inch baking pan and parchment paper will simplify baking and cleanup. A stand mixer speeds up beating the eggs and sugars, but a hand mixer or vigorous whisk will work too.
Pin This Recipe
These sourdough discard brownies are an easy, satisfying way to use extra starter and enjoy a rich, chocolaty treat. They’re beginner-friendly, freezer-friendly, and perfectly chewy—give them a try the next time your starter needs a purpose.
