These sourdough discard brownies are ultra-fudgy, subtly tangy, and perfectly sweet. If you're looking for a way to satisfy your sweet tooth while using up some of your sourdough discard, this is the recipe for you — I've tested it countless times and I know you're going to love it!
For another rich chocolate dessert that's soft, sliceable, and easy to share, try my chocolate sheet cake with chocolate cream cheese frosting. Looking for more brownie variations? Try my brownie crumb bars and my zucchini brownies! And for another chocolate sourdough favorite, my sourdough chocolate peanut butter swirl cookies are an all-time best.
Quick Look: Sourdough Discard Brownies
⏱️ Ready In: About 40 minutes
🔥 Bake Time: 30–35 minutes
🍽️ Serves: 9 brownies
✨ Calories: Approximately 449 per brownie
🥄 Main Ingredients: Sourdough discard, chocolate chips, cocoa powder, butter
🌿 Dietary Info: Vegetarian (easily made dairy-free)
💛 Why You'll Love It: Ultra-fudgy, shiny-topped brownies that use up your sourdough discard.
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Why You'll Love This Recipe
- Ultra-fudgy texture: Melted butter, oil, melted chocolate, and an extra egg yolk give these a dense, fudgy crumb — never cakey.
- A great way to use discard: A perfect home for that jar of starter in your fridge, just like my sourdough double chocolate banana muffins.
- That glossy, crackly top: The high-fat batter is the secret to a shiny, paper-thin crust on top.
- Subtly tangy depth: The discard adds a faint tang that balances all that chocolate, the same trick that makes my sourdough discard funfetti layer cake so good.
- Quick and one-bowl: No mixer required and ready in about 40 minutes — perfect for a holiday dessert (like my cinnamon sugar biscoff blondies) or a weeknight chocolate fix.
Jump to:
- Quick Look: Sourdough Discard Brownies
- Why You'll Love This Recipe
- Ingredients
- Easy Substitutions & Variations
- How to Make Sourdough Discard Brownies
- Expert Tips
- What Makes This Recipe Special?
- Sourdough Discard Brownies FAQs
- Fudgy Sourdough Discard Brownies Troubleshooting Guide
- Storage
- Other Chocolate Recipes to Consider
- The Best Sourdough Discard Brownies
Ingredients
- unsalted butter + neutral oil: Melted together for a rich, fudgy base and a glossy top.
- chocolate chips: Melted into the butter for deep chocolate flavor.
- cane sugar + brown sugar: The mix keeps the brownies sweet, moist, and chewy.
- eggs + extra egg yolk: The extra yolk adds fat for fudginess and that shiny crust.
- vanilla extract: Rounds out the chocolate.
- sourdough discard: The star — straight from the fridge, adding moisture and a subtle tang.
- cacao/cocoa powder: For intense, true chocolate flavor.
- all-purpose flour + cornstarch: Just enough structure; the cornstarch keeps them tender.
- milk powder + salt: Milk powder deepens the flavor (optional); salt balances the sweetness.
See the recipe card for quantities.
Easy Substitutions & Variations
- Butter: Use a non-dairy plant butter. Since plant butter sticks contain salt, reduce the added salt to ½–¾ teaspoon.
- Milk powder: Omit it to make these dairy-free — they'll still be fudgy.
- Gluten-free: Try a 1:1 gluten-free flour blend (untested by me, but it should work).
- Mix-ins: Fold in extra chocolate chips, walnuts, pecans, or swirls of peanut butter for a fun twist — like a fudgy cousin of my chocolate chunk banana bread.
How to Make Sourdough Discard Brownies
Note: I bake by weight for accuracy. Cup measurements are approximate and may vary depending on how you scoop.
Step 1: Melt the chocolate: Preheat your oven to 350°F. In a small saucepan over medium-low heat, melt the butter and oil, stirring regularly. Add the chocolate chips.
Step 2: Whisk until smooth: Whisk until fully incorporated and glossy, then let cool slightly and transfer to your mixing bowl.
Step 3: Add the wet ingredients: Add the cane sugar, brown sugar, eggs, egg yolk, vanilla, and sourdough discard to the melted chocolate. Stir until combined.
Step 4: Add the dry ingredients and bake: Add the cacao powder, flour, milk powder, salt, and cornstarch. Mix until combined, then transfer to a parchment-lined 9x9 baking dish.
Bake 30–35 minutes, removing them when the center is firm but jiggles slightly when shaken.
Weigh your ingredients! Using a kitchen scale ensures your measurements are accurate, which is key for getting consistent results in baking. It takes the guesswork out of measuring and helps your recipes turn out exactly as intended every time.
Expert Tips
- Pull them when the center still jiggles. For the fudgiest brownies, take them out when there's a subtle, firm jiggle in the center — they finish baking in the pan and won't dry out.
- Cool fully before cutting. As tempting as it is, let them cool completely for clean slices and the best fudgy texture.
- Use parchment paper. Line the pan and leave an overhang to lift the whole slab out easily.
- Don't skip the extra yolk. The high fat ratio is what gives you that signature shiny, crackly top.
- Let the chocolate cool slightly. Add it to the sugars and eggs warm, not hot, so you don't scramble the eggs.
What Makes This Recipe Special?
The sourdough discard does something subtle but real here — it adds moisture and a faint tang that keeps these from tasting flatly sweet, the same depth I love in my sourdough malted chai chocolate chip cookies.
The other secret is the fat. Melted butter, coconut oil, melted chocolate, and an extra egg yolk all work together for that dense, fudgy interior and glossy, crackly top. Serve them warm with ice cream, or alongside my chocolate espresso cinnamon rolls for a full chocolate spread.
Sourdough Discard Brownies FAQs
Shiny tops come from a high-fat batter — that's why we use melted butter, oil, melted chocolate, and more egg yolk relative to whites.
No — unfed discard straight from the fridge works perfectly here.
Yes. Use a plant butter (reduce the salt to ½–¾ teaspoon since it's salted) and omit the milk powder.
Pull them when the center is firm but jiggles slightly when you shake the pan. They'll finish setting as they cool for the fudgiest result — perfect served with a slice of chocolate sour cream pound cake cupcakes on a dessert tray.
Fudgy Sourdough Discard Brownies Troubleshooting Guide
| Problem | Cause | Fix |
|---|---|---|
| Cakey, not fudgy | Overbaked or too much flour. | Pull when the center still jiggles slightly; measure flour by weight. |
| No shiny top | Not enough fat, or sugar not dissolved. | Use the full butter/oil/chocolate/yolk and stir sugars into the warm chocolate. |
| Crumbly when cut | Cut while still warm. | Cool completely before slicing. |
| Too salty | Salted plant butter used. | Reduce added salt to ½–¾ teaspoon when using plant butter. |
| Greasy texture | Chocolate mixture too hot when mixed. | Let the melted chocolate cool slightly before adding eggs. |
Storage
- Cover with cling wrap and store on the counter for 2–3 days, or in the fridge for 5–7 days.
- These freeze well for up to 6 months — wrap tightly and thaw at room temperature.
Other Chocolate Recipes to Consider
Did you make this recipe?
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The Best Sourdough Discard Brownies
Equipment
- 9x9 baking dish
- mixing bowl
- Parchment Paper
- Silicone spatula
- Kitchen Scale
Ingredients
- 113 grams unsalted butter melted (½ cup)
- 1 tablespoon neutral oil
- 170 grams chocolate chips 1 cup
- 200 grams cane sugar 1 cup
- 100 grams brown sugar packed (½ cup)
- 2 large eggs
- 1 egg yolk
- 2 teaspoons vanilla extract
- 150 grams sourdough discard ½ cup
- 120 grams all-purpose flour 1 cup
- 45 grams cacao/cocoa powder ½ cup
- 1 teaspoon salt
- 2 tablespoons milk powder optional
- ½ tablespoon cornstarch
Instructions
- Preheat oven to 350°F. In a small saucepan, melt the butter and oil over medium-low heat, stirring regularly. Once melted, add the chocolate chips and whisk until smooth. Allow to cool slightly, then transfer to your mixing bowl or stand mixer.113 grams unsalted butter, 1 tablespoon neutral oil, 170 grams chocolate chips
- Add the cane sugar, brown sugar, eggs, egg yolk, sourdough discard, and vanilla extract to the melted chocolate mixture. Stir until combined.200 grams cane sugar, 100 grams brown sugar, 2 large eggs, 1 egg yolk, 2 teaspoons vanilla extract, 150 grams sourdough discard
- Add the cacao or cocoa powder, flour, milk powder, salt, and cornstarch. Mix until combined and transfer to a parchment-lined 9x9 baking dish.120 grams all-purpose flour, 45 grams cacao/cocoa powder, 1 teaspoon salt, 2 tablespoons milk powder, ½ tablespoon cornstarch
- Bake uncovered for 30–35 minutes. Remove from the oven when the center is firm but jiggles slightly when you shake it — it will finish baking outside the oven for a very fudgy brownie.
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