Sourdough Brownies

I’ve been baking with the same sourdough starter since 2014, and people often ask what I do with all the discard. The answer is simple: I use it. When my starter is weak from neglect and needs to be fed in order to raise a lofty loaf of bread, I never actually get rid of the starter. Instead, I incorporate it into lightly leavened baked goods like pancakes, waffles and sourdough brownies.

These sourdough discard brownies have all the same elements as our best brownies: an intensely chocolaty taste from cocoa powder in the batter and a smattering of dark chocolate chunks in each bar. The brownies bake as soon as they’re mixed, so the sourdough doesn’t really have time—or the need—to work the leavening magic that gives sourdough bread its airy crumb. Instead, these brownies have a rich, fudgy quality with a tanginess reminiscent of cream cheese. With this recipe, you know you’re going to be eating decadent brownies, not fluffy chocolate cake.

Ingredients for Sourdough Brownies

• Butter: This sourdough brownie recipe uses melted butter to bloom the cocoa powder for deep flavor and dissolve any lumps. Our favorite butter brands bake up beautifully into brownies.
• Sugar: Granulated sugar dissolves quickly and sweetens the bitter baking cocoa and sour starter. To keep the sugar from burning, heat everything in a double boiler and stir often. If you don’t have a double boiler, set a metal bowl over a saucepan of simmering water, making sure the bowl doesn’t touch the water.
• Baking cocoa: Baking cocoa gives these brownies their chocolate potency. Natural cocoa powder is slightly acidic and heightens the tanginess of sourdough. If you’d rather tone down the sour notes, use Dutch-processed cocoa. Both are unsweetened.
• Salt: Salt has a surprisingly powerful role in baking, making sugary desserts taste sweeter and balancing the flavor of leavened doughs. Sourdough pizza dough crust tastes flat without salt—even under all the toppings. Just a little salt significantly enhances the flavor of these brownies.
• Instant espresso powder: There’s another secret ingredient for better chocolate desserts: instant espresso powder. Just as salt makes brownies taste sweeter, espresso makes them taste more chocolaty.
• Vanilla extract: For the best-tasting brownies, buy pure vanilla extract. You can also make vanilla extract at home; like baking with sourdough, it takes little effort but bit of time.
• Eggs: It’s always easiest to beat room-temperature eggs into batter, but taking them from the fridge early becomes especially important when stirring them into warm ingredients. Eggs just below the temperature of the melted butter mixture, beaten in one at a time, are unlikely to cook into scrambled curds.
• Sourdough starter: Lively and sluggish sourdough starters, of any hydration level, work equally well in this recipe. When you take starter from your jar and use it in these brownies, you make room to feed your remaining starter. If you’ve already fed your starter and it has begun to expand, stir it down to get an accurate volume.
• Flour: Sourdough starter is a blend of flour and water, so sourdough discard brownies need minimal flour to firm up the batter. It’s not a problem if you feed your starter with a different type of flour, but you should use all-purpose flour for this recipe.
• Chocolate chips or chunks: One way to make brownies better is to stir dark chocolate chips or chunks into the cocoa-based batter. As the pieces melt in the oven, they create gooey pockets in the brownies.

Directions

Step 1: Prepare the pan

Preheat the oven to 350°F. Line an 8-inch square baking pan with parchment.

Editor’s Tip: Lining the baking pan is a simple yet easily overlooked tip that will take your baking from good to great. To easily remove the baked brownies from the pan, let the parchment extend past the sides so that you can grab the edges and lift the entire slab free.

Step 2: Make the chocolate base

Bring a few inches of water to a low simmer in the bottom of a double boiler. Add the butter, sugar, baking cocoa and salt to the top of the double boiler. Stir occasionally until the butter melts and the mixture is warm to the touch.

Step 3: Stir in flavorings

Add the vanilla and espresso powder, and then stir to combine. Remove the bowl from the heat.

Step 4: Beat in the eggs and starter

Add the eggs, one at a time, beating until the batter appears smooth and glossy.

Add the sourdough starter, stirring until it’s incorporated.

Step 5: Finish the batter

Add the flour and stir just until the flour is moistened and no dry patches remain. Fold in the dark chocolate.

Editor’s Tip: Avoid overmixing the batter (it’s one of the mistakes everyone makes when baking brownies) so that the baked squares stay dense and fudgy. Without a quick-acting leavener like baking soda or baking powder, excessive mixing won’t make these brownies airy, but it might make them gummy.

Step 6: Bake the brownies

Transfer the batter to the prepared pan and spread it into an even layer. Bake the brownies for 24 to 26 minutes or until they appear set and a toothpick inserted into the center comes out almost clean.

Step 7: Cool and slice the brownies

Transfer the pan to a wire rack to cool completely. Slice the brownies into squares to serve.

Editor’s Tip: We recommend using a thin metal bench scraper to cut dessert bars like a pro. The tool lets you slice straight down through the brownie slab, minimizing crumbs and snapping out even squares.

Sourdough Brownies Variations

• Brown the butter: Go beyond melting and use brown butter for these brownies. Cooking butter longer over low heat gives it a nutty flavor and evaporates most of its water, which can keep brownies from becoming gloppy if your sourdough starter is fairly fluid.
• Change the extract: Instead of vanilla, use rum extract to give the brownies a suggestion of booziness without the alcohol. Mint and orange extracts also play well with these brownies.
• Sprinkle on a garnish: As soon as you pull the brownies from the oven, sprinkle them with flaky sea salt for a salted chocolate effect. Or hit them with sifted cocoa powder or confectioners’ sugar for a simple yet attractive finish.

How to Store Sourdough Brownies

Store sourdough brownies on the counter or in the refrigerator, either in a lidded container or wrapped well. Let them cool completely before packaging them—or even before cutting the full pan into bars. Just-cooked brownies will crumble when sliced, and will spoil more quickly if wrapped when warm.

How long do sourdough brownies last?

Sourdough brownies last for up to four days at room temperature. If you put them in the fridge, they’ll keep well for up to a week.

Can you freeze sourdough brownies?

Sourdough brownies freeze well for up to three months. Freezing brownies as a solid slab keeps their center moist and consistent through the freeze-and-thaw cycle. Wrap the entire 8-inch square tightly before freezing. To thaw it, unwrap the square and set it on a large plate on the counter. If you want to thaw one brownie at a time, pack the cut bars in an airtight container, alternating the brownies with pieces of parchment.

Sourdough Brownies Tips

How do I get more sourdough flavor in brownies?

Using more sourdough starter would give you more sourdough flavor, but it would also affect the recipe’s balance and produce overly soft, tacky brownies. Instead, the trick to stronger sourdough tang is to use older, unfed starter. A jar of starter funking out at the back of your fridge is just the ticket for sourdough discard recipes. The dark, acidic liquid that covers the surface merely means your starter is hungry. Stir in this liquid and then measure out the starter for maximum flavor in sourdough brownies.

If you prefer mellower sourdough brownies, the opposite is true: Pour off the liquid before you use the starter, or go a step further and feed your starter before you mix it into brownie batter. Whether you incorporate or drain off the liquid, you should feed your starter after you make sourdough brownies and let it double in volume before baking with it.

How should you serve sourdough brownies?

Sourdough brownies taste heavenly on their own; just wait at least 30 minutes after baking to slice them so that they don’t fall apart. They complement the decadence of Viennese coffee, but taste just as delicious alongside a basic cup of coffee or tea. Enjoy a square with a full-bodied red wine or a rye whiskey-based Sazerac. Class up your sourdough brownies into a showy dessert topped with creme fraiche and fresh raspberries to emphasize their tang, with or bourbon ice cream and candied pecans to enhance their rich sweetness.