Extra Fudgy Sourdough Discard Brownies

Sourdough discard brownies are what I bake when the starter jar is overflowing and I'd rather not bin the excess. These are properly fudgy, with a shiny crackly top, dark chocolate flavour and a faint tang that makes them taste more interesting than a plain brownie. There's no extra flour in the recipe, because the discard does that job (here's Sourdough Discard 101 if you're new to it).

Jump to:

• Recipe Highlights
• DISCARD IN BROWNIES?
• Ingredients and Substitutes
• Equipment Needed
• Christmas Sourdough ebook
• Step-By-Step Method
• Recipe Video
• Tips for the Best Sourdough Brownies
• How To Serve Sourdough Brownies?
• Storage
• Other Sourdough Discard Recipes To Try
• Fudgy Sourdough Discard Brownies
• Recipe FAQ

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DISCARD IN BROWNIES?

Sourdough discard brownies are fudgy chocolate brownies made with unfed sourdough starter, the portion you'd normally scrape off before feeding. In this recipe the discard replaces the flour completely, so there's no plain (all-purpose) flour in the ingredients list.

That works because your starter is already flour and water. At 100% hydration (equal weights of each), 120 g of starter brings roughly 60 g of flour and 60 g of water into the batter. It's enough structure for a dense, fudgy brownie, and not enough to turn it into chocolate cake.

I bake with discard constantly on Somebody Feed Seb, and brownies are where it earns its keep. Three things happen here:

1. Moisture. The water in the starter keeps the crumb damp and dense, which is exactly what you want from a fudgy brownie. I use the same trick in my Sourdough Blondies.
2. Depth of flavour. Discard brings a faint acidity that cuts through the sweetness, the way a pinch of salt does. It makes the chocolate taste more complex without making the brownies taste sour.
3. No extra flour. Less flour means less chance of a cakey crumb, and one less thing to measure.

Ingredients and Substitutes

• Dark chocolate: 52 to 54% cocoa solids is your best option, broken into small pieces. Semi-sweet chocolate chips work too.
• Unsalted butter: salted butter is fine if that's what you have, just reduce the salt to ¼ tsp.
• Vegetable oil: butter gives flavour, and the oil keeps the brownies soft once they've cooled. Rapeseed (canola) or sunflower oil both work. Don't use olive oil, the flavour takes over.
• Eggs and egg white: large in the UK, extra-large in the US.
• Caster sugar and light brown sugar: you need both. Caster sugar (also called superfine sugar, and any white granulated sugar will do) gives the crisp edges and the crackly top. Light brown sugar adds molasses, which makes the middle chewier and fudgier. Dark brown sugar works if that's what's in the cupboard.
• Unsweetened cocoa powder: regular (natural) unsweetened cocoa is what I use. Dutch process cocoa gives an even deeper chocolate flavour if you want to try it.
• Vanilla bean paste: vanilla extract is fine instead.
• Sourdough starter discard: active starter works too. Either way, the recipe is written for a 100% hydration starter.

Find the quantities and step-by-step instructions in the recipe card at the bottom of the post. 

Equipment Needed

• medium pan: for melting butter and chocolate. 
• electric handheld mixer: we use and love the Kenwood electric mixer. 
• rubber spatula: or a wooden spoon. 
• square 24x24 cm baking tray: or other high-rimmed tray with a similar surface area. I do not recommend using a glass or ceramic baking dish for baking brownies in!
• baking parchment paper: we always use and love Bacofoil Baking Parchment. 

Step-By-Step Method

Prepare the tin. Preheat the oven to 180°C Fan (200°C / 400°F). Line the baking tin with parchment paper.

Melt the chocolate. Put the butter, chocolate and vegetable oil in a medium pan over low heat. Stir now and then until the butter has melted, then take the pan off the heat and leave it. The residual heat melts the chocolate, so there's no need to keep stirring over the hob.

Whisk the eggs and sugar. In a large bowl, whisk the eggs, egg white, salt, vanilla, caster sugar and light brown sugar with the handheld mixer.

Keep going until the sugar has dissolved and the mixture is light and fluffy. Don't rush this bit. It's what builds the crackly top.

Combine. Add the cocoa powder and sourdough discard to the melted chocolate and mix until smooth. Pour the chocolate mixture into the egg mixture and fold gently until you can't see any streaks. Stop there.

Bake. Pour the brownie batter into the prepared tin and bake in the centre of the oven for 30 to 35 minutes. The top should be shiny and the edges set and slightly firm. A toothpick in the centre should come out with a few moist crumbs, not wet batter.

Cool. Leave the brownies to cool and firm up for at least 30 minutes before slicing. The top cracks neatly when you cut it.

Recipe Video

Tips for the Best Sourdough Brownies

🥄 Dissolve the sugar properly. Grainy sugar in the egg mixture means a dull, flat top. If you want that shiny, crackly surface, keep whisking until the mixture is smooth and light.

🍫 Fold, don't beat. Once the chocolate goes in, you're only trying to combine. Overmixing adds air and weakens that thin top crust.

🔥 Watch the clock. Underbaked brownies can't form a proper crust, and overbaked ones turn dry on top. Start checking at 30 minutes. Edges set, top shiny, a few moist crumbs on the toothpick.

⏳ Be patient with the cooling. Cut too early and you'll have brownie pudding. Not a bad outcome, but not the brief.

📄 Leave a little parchment overhanging on two sides of the tin so you can lift the whole slab out before slicing.

How To Serve Sourdough Brownies?

Let them cool and firm up first, then slice. Serve at room temperature, or warm a slice in the microwave for 15 to 20 seconds.

• A dusting of icing sugar and a scoop of vanilla ice cream is the classic.
• A dollop of creme fraiche is even better. The tartness balances the rich chocolate.
• Chantilly cream with cherry compote or raspberry coulis for something that looks like you tried harder than you did.

Storage

Slice the brownies into portions and store them in an airtight container at room temperature for 3 to 4 days, or in the fridge for up to 1 week. If you're stacking them, put a sheet of parchment between the layers.

To freeze, wrap each slice tightly in cling film (plastic wrap) and put the slices in an airtight container or freezer bag. Thaw at room temperature for a couple of hours.

Other Sourdough Discard Recipes To Try

Looking for more sourdough discard recipes? Try Sourdough Chocolate Chip Cookies, Sourdough Sugar Cookies or Overnight Sourdough Pancakes (or Sourdough Blueberry Pancakes) next!

You mustn't miss our Sourdough Lemon Poppy Seed Muffin recipe and Sourdough Canelés either!

Need even more ideas? Find lots of sourdough recipes that aren't bread here!

Recipe FAQ