Sourdough Discard Brownie Recipe

I absolutely refuse to let my sourdough discard go to waste, which is why I love finding new ways to incorporate it into my baking for hearty home cooking. This easy sourdough discard brownie recipe transforms unfed starter into rich, fudgy brownies that are deeply chocolatey, with no sour taste at all. We are elevating this classic with a unique twist: a spiced dulce de leche ribbon, creating a dessert that feels extra special yet requires simple pantry ingredients.

The texture is dense and chewy, thanks to the combination of melted butter and sourdough discard. Get ready to bake a new family favorite that elevates the humble brownie to gourmet status.

Ingredients

• 170 g (3/4 cup) Unsalted Butter: The base for our fudgy texture. Melting the butter ensures a dense, chewy result rather than a cake-like crumb. If using salted butter, reduce the added fine sea salt to 1/4 teaspoon.
• 200 g (1 cup) Granulated Sugar and 100 g (1/2 cup, packed) Light Brown Sugar: The combination provides both sweetness (granulated) and moisture/chewiness (brown sugar). The brown sugar also adds a subtle caramel note that complements the dulce de leche.
• 2 Large Eggs and 10 ml (2 teaspoons) Alcohol-Free Vanilla Extract: Provide structure and richness to the brownies. The eggs bind the ingredients together, creating a thick batter. Alcohol-free vanilla extract is often preferred as it imparts a rounder flavor during baking.
• 120 g (1/2 cup) Sourdough Discard (unfed or active): Adds depth of flavor and moisture without requiring a separate leavening agent. Use discard that has not been fed in 12-24 hours; it will not contribute sourness, only a slight tang that enhances the chocolate.
• 75 g (3/4 cup) Unsweetened Cocoa Powder (Dutch-processed recommended): Provides the rich, dark chocolate flavor. Dutch-processed cocoa results in a deeper, smoother chocolate taste and a darker color. If using natural cocoa powder, the flavor will be slightly sharper, but still delicious.
• 75 g (2/3 cup) All-Purpose Flour: The structural element of the brownie; provides body and chewiness. Be careful not to measure too much flour, as it can make the brownies dry and dense. To measure accurately, spoon the flour into the measuring cup and level it off.
• 5 g (1 teaspoon) Baking Powder: Adds a touch of lift to prevent the brownies from being too dense and heavy. While sourdough discard adds leavening, the baking powder ensures a slightly puffed texture in this sourdough discard brownie recipe. Do not omit this if you want a lighter, fudgier texture.
• 3 g (1/2 teaspoon) Fine Sea Salt: Enhances the chocolate flavor and balances the sweetness. Fine sea salt dissolves easily in the batter; avoid coarse salt. This small amount is crucial for depth of flavor in this sourdough discard brownie recipe.
• 170 g (1 cup) Dark or Semi-Sweet Chocolate Chips or Chopped Chocolate: Folded in for extra puddles of melted chocolate throughout the brownie. Use high-quality chips (60-70% cacao) for best results, or chop up a good baking bar.
• 397 g (14 oz) Can Dulce de Leche: Creates the signature caramel swirl. Use canned dulce de leche (often found in the international or baking aisle) for convenience. Avoid using regular caramel sauce, as it is too thin for swirling.
• 5 g (1 teaspoon) Ground Cinnamon (divided) and 1 g (1/4 teaspoon) Ground Cardamom or Nutmeg: The spice blend adds warmth and complexity to the dulce de leche. Cardamom adds a unique floral note; nutmeg provides a more classic warmth.
• Pinch of Fine Sea Salt (for dulce de leche): Brightens the flavor of the caramel. This small addition makes the dulce de leche taste more balanced and complex.

Instructions

1. Prep the Pan and Oven: Preheat your oven to 175°C (350°F). Line a 23×23 cm (9×9 inch) baking pan with parchment paper, allowing an overhang on two sides to easily lift the brownies out later. Lightly grease the parchment paper with butter or cooking spray.

2. Combine Sugars and Butter: In a large bowl, combine the melted butter, granulated sugar, and light brown sugar. Whisk thoroughly for 1-2 minutes until smooth and well combined; the mixture will start to look slightly emulsified. This step helps dissolve some of the sugar before adding other ingredients.

3. Add Eggs, Vanilla, and Discard: Add the eggs one at a time, whisking well after each addition until fully incorporated. Stir in the alcohol-free vanilla extract and sourdough discard until just combined. The batter will look thick and glossy at this point.

4. Mix Dry Ingredients and Fold in Chocolate Chips: In a separate medium bowl, whisk together the cocoa powder, all-purpose flour, baking powder, and 3g (1/2 teaspoon) fine sea salt. Gradually add the dry ingredients to the wet ingredients, mixing with a spatula until just combined. Do not overmix; stop folding once you see no more streaks of flour. Fold in the chocolate chips last. My kids are usually helping me here, so I always make sure we stop as soon as those last flour streaks disappear to avoid tough brownies.

5. Prepare Spiced Dulce de Leche: In a small microwave-safe bowl, combine the dulce de leche, 4g (3/4 teaspoon) of the ground cinnamon, ground cardamom or nutmeg, and the pinch of fine sea salt. Microwave for 15-20 seconds or gently warm over low heat on the stovetop until slightly loosened and stirrable. Reserve 2 tablespoons of the spiced dulce de leche for garnish.

6. Layer and Swirl: Pour half of the sourdough discard brownie batter into the prepared baking pan and spread evenly with an offset spatula. Spoon half of the remaining spiced dulce de leche over the batter in dollops. Carefully pour and spread the remaining sourdough discard brownie batter over the dulce de leche layer. Spoon the last of the spiced dulce de leche over the top batter.

7. Create the Ribbon: Use a butter knife or skewer to gently swirl the dulce de leche into the top layer of sourdough discard brownie batter, creating visible ribbons. Do not over-swirl, or the dulce de leche will disappear completely into the chocolate batter. The goal is to see distinct ribbons of caramel throughout the top.

8. Bake until Set: Bake for 30-35 minutes, or until a toothpick inserted into the center (avoiding a dulce de leche ribbon) comes out with moist crumbs, not wet batter. The edges should be set and slightly puffed; the center should still look soft. If a clean toothpick comes out, the sourdough discard brownies are overbaked and will be dry.

9. Cool Completely: Let the brownies cool completely in the pan on a wire rack, which is crucial for achieving clean cuts and a fudgy texture. Cooling allows the ingredients to set properly and prevents crumbling when cutting. Once cool, use the parchment paper overhang to lift the brownies from the pan and transfer to a cutting board.

10. Garnish and Serve: Cut the cooled brownies into 9 or 16 squares. Gently rewarm the reserved 2 tablespoons of spiced dulce de leche if needed, then drizzle decoratively over the brownie or plate. Finish with a very light dusting of the remaining 1g (1/4 teaspoon) ground cinnamon for aroma and visual contrast.

Tips for the Ultimate Fudgy Texture and Crinkly Top

Getting a truly fudgy brownie isn’t just about the ingredients; it’s also about a few key techniques. Keep these tips in mind as you bake this particular sourdough discard brownie recipe.

• Don’t Overmix the Batter: When combining the dry ingredients with the wet, stop mixing as soon as the flour streaks disappear. Overmixing develops gluten, which leads to a tough, cake-like brownie instead of a truly fudgy one.
• The Importance of Brown Sugar: The light brown sugar in this recipe adds moisture that helps keep the final texture soft and chewy, while also enhancing the caramel notes from the dulce de leche.
• Patience is Key for Cutting: Cutting brownies while warm or hot will result in messy, crumbly edges. Allow them to cool completely in the pan on a wire rack before attempting to slice for clean, crisp edges. My kids are always hovering when these come out of the oven, but I’ve learned the hard way that cutting them warm results in a delicious mess. Wait for clean cuts.
• Achieving the Crinkly Top: The combination of melted butter, thorough whisking of the sugars and eggs, and proper cooling helps create that shiny, paper-thin crinkle top characteristic of a great fudgy brownie.

Spiced Dulce de Leche Swirl Variations and Substitutions

This sourdough discard brownie recipe is versatile. Here are some simple adjustments you can make to fit your kitchen and preferences.

• Spice Customization: The combination of cinnamon and cardamom or nutmeg adds a warm, aromatic dimension to the dulce de leche swirl. If you don’t have cardamom, simply use 1 teaspoon of cinnamon instead.
• Dulce de Leche Shortcut: Canned dulce de leche is convenient, but you can also make your own by slowly simmering a can of sweetened condensed milk for several hours. Just ensure it’s thick enough to hold its shape when swirling.
• Chocolate Variations: If you don’t enjoy semi-sweet chocolate, try milk chocolate chips for a sweeter brownie, or increase the dark chocolate percentage to 70-80% for an even deeper, less sweet flavor profile.
• Nutty Additions: For a bit of crunch, fold 1/2 cup of toasted pecans or walnuts into the batter along with the chocolate chips.

Using Sourdough Discard in Brownies: FAQs

Does this sourdough discard brownie recipe taste sour?

No, when using discard in baked goods like brownies, the fermentation adds complexity and a slightly deeper flavor without tasting strongly sour. The sugar and chocolate mask any potential tang. It’s truly a delicious way to use up unfed starter in a family-friendly dessert.

Can I use my active starter instead of discard?

Yes, you can use active starter, but it will affect the texture slightly. Unfed discard is preferred because it’s less active, allowing the baking powder to do most of the leavening work for a specific texture. Active starter may make the final product slightly cakier and less dense.

What is the purpose of the baking powder in a sourdough discard brownie recipe?

Since the discard isn’t used for leavening here, the baking powder ensures the brownies have a slightly higher rise and a lighter, fudgier crumb rather than being completely flat and dense. It prevents a heavy, gummy texture.

Can I make this sourdough discard brownie recipe gluten-free?

Yes, this recipe works beautifully with a 1:1 gluten-free flour blend. I have tested this with several brands, and the texture remains close to the original. Just ensure your discard is made from gluten-free flour as well.

Can I freeze these brownies?

Yes, once cooled completely, cut the brownies and wrap each square individually in plastic wrap, then store them in an airtight container in the freezer for up to 3 months. Thaw at room temperature before serving; I always cut these for easy meal prep before freezing them. To reheat, warm a square in the microwave for 15-20 seconds.

What’s the best way to store leftovers?

Store cut brownies in an airtight container at room temperature for up to 3 days, or refrigerate for up to a week. For longer-term storage, follow the freezing instructions above. The flavor often deepens slightly overnight, making them an excellent healthy snack or dessert option.

Conclusion

This easy sourdough discard brownie recipe is the perfect solution for using up unfed starter in a way that truly feels like a treat. The spiced dulce de leche swirl adds a level of sophistication that makes these brownies perfect for any special occasion or just a cozy night in. Don’t wait for your next feeding day—whip up this recipe and share a batch with friends and family this week. Save this recipe on Pinterest so you can keep making these fudgy brownies for years to come.

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