Sourdough Discard Brookies (The Best of Brownies and Cookies!)
Most sourdough brookie recipes treat the cookie layer like an afterthought, but mine doesn’t! A full cup of sourdough discard goes into both layers for extra moist brookies with deeper chocolate flavor, a crackly brownie top, and a chewy, golden cookie layer. I tested them over and over until both layers baked perfectly together, and they stay soft for days. They’re the one dessert everyone can agree on!
Give my sourdough brownies a try too!
These sourdough brookies are the best of both worlds! They have a rich, fudgy brownie on the bottom and a chewy, golden chocolate chip cookie on top, all baked together in one pan.
Sourdough discard goes into both layers, giving you a deeper, more bakery style flavor and an extra moist texture. They’re easy to make, perfect for using up your discard, and always the first thing to disappear at parties.
I can never decide between brownies and chocolate chip cookies, and neither can my family. My husband is a chocolate chip cookie guy, my kids always want brownies, and I just want whatever has the most chocolate. These sourdough brookies ended that debate in our house for good.
I tested this recipe over and over until I got the bake just right, because the hardest part of any brookie is getting a fully baked cookie layer without overbaking the brownie underneath. My early batches either had a raw cookie top or dry brownie edges, so I’m sharing every tip I learned so yours come out perfect the first time.
Jump to:
- Why You’ll Love These Sourdough Brookies
- What Are Brookies?
- Ingredients to Gather
- What Does Sourdough Discard Do in Brookies?
- Sourdough Discard vs. Active Starter
- Substitutions and Variations
- Holiday Sourdough Brookies
- Step by Step Instructions
- How to Tell When Sourdough Brookies Are Done
- Tips for the Best Sourdough Brookies
- Overnight Sourdough Brookies (Optional Cold Ferment)
- Troubleshooting Sourdough Brookies
- How to Serve Sourdough Brookies
- Storage Info
- How to Freeze Sourdough Brookies
- Frequently Asked Questions
- More Sourdough Dessert Recipes
- 📖 Recipe
Why You’ll Love These Sourdough Brookies
- It's two desserts in one! Fudgy sourdough brownie and chewy sourdough chocolate chip cookie in every bite. I had my first brookie from Trader Joe's and I knew I had to try make some myself!
- Uses up a full cup of sourdough discard across both layers. If you are like me and always have a jar of sourdough discard in your fridge, this is a great place to use it!
- Extra moist and stays soft for days. I made a batch and gave them to my kids for lunchbox dessert all week! They were just as good on Friday as they were on Monday.
- One pan feeds a crowd with 24 brookies. I was able to give some to my friends plus keep some for my family. And everyone loved them!
- Make ahead and freezer friendly, perfect for parties, bake sales, and holiday cookie trays.
- Easy to customize with peanut butter, mint, espresso, holiday sprinkles, and more.
What Are Brookies?
A brookie is a brownie and a chocolate chip cookie baked together. The most popular version layers cookie dough on top of brownie batter in a baking pan, then bakes them together so you get a crackly, golden cookie top and a fudgy brownie base.
Some people swirl the two together or even bake them as round cookies, but the layered bar version is the classic and the one I make most often.
A friend brought them to our house in Maine over the summer and my kids fell in love! Once the fall came and I was baking again, I knew I needed to make some sourdough brookies with my discard ASAP!
Ingredients to Gather
You'll need to make both the brownie layer and the chocolate chip layer so I separated the ingredients into both.
For the Sourdough Brownie Layer
- Butter. Melted butter gives the brownies their fudgy texture and shiny, crackly top.
- Granulated sugar. This helps create that crinkly brownie top, plus all brownies need a little sugar!
- Eggs. Room temperature eggs whip up better for a crackly top.
- Vanilla extract. Rounds out the chocolate flavor.
- Sourdough discard. 100% hydration discard, unfed, straight from the fridge. If you only have sourdough starter that is active, that will work too! Since we aren't letting this ferment, active starter or sourdough discard will work.
- Cocoa powder. Unsweetened natural or Dutch process cocoa both work. Dutch process gives a darker, richer brownie.
- All-purpose flour. Just enough to hold everything together while keeping it fudgy.
- Salt. Balances the sweetness.
- Chocolate chips. For pockets of melty chocolate in the brownie layer. Mini semi sweet chocolate chips or regular chocolate chips will work.
For the Sourdough Cookie Layer
- Butter. Melted for a chewy cookie layer. I always use salted butter (sorry, not sorry). If you have unsalted butter or salted butter, either will work!
- Brown sugar. Adds chewiness and caramel flavor.
- Granulated sugar. Helps the edges get golden. Most chocolate chip cookies have both brown sugar and granulated sugar.
- Egg. Binds the cookie dough.
- Vanilla extract. For classic chocolate chip cookie flavor.
- Sourdough discard. Adds a little but of tang and moisture. Plus it helps reduce waste since we are using the discard.
- All-purpose flour. Gives the cookie layer its structure.
- Baking soda. Helps the cookie layer rise and turn golden.
- Salt. Balances the sweetness.
- Chocolate chips. Semi-sweet are my go-to, but milk or dark chocolate work too.
Be sure to check out the printable recipe card for full recipe information on ingredients and quantities.
What Does Sourdough Discard Do in Brookies?
Sourdough discard adds a little extra moisture and a gentle tang that makes the chocolate taste richer and more complex, a lot like how a pinch of espresso makes chocolate taste more chocolatey.
It doesn’t make the brookies sour at all. Since these brookies get their rise from eggs and baking soda, the discard is there purely for flavor and texture, so you can use discard straight from the fridge without feeding it.
I’ve tested these with discard that was a day old and discard that was over a week old, and both work great. Older discard gives a slightly tangier flavor, which I actually love against the sweet chocolate. I love using it in my sourdough biscotti too!
Sourdough Discard vs. Active Starter
You can use either one in this recipe. I like discard best because it’s the perfect way to use it up, but active starter works the same way since these brookies don’t rely on the starter to rise.
The one thing to watch is consistency, if your starter is very thick or a low hydration, stir in a tablespoon of water first so it mixes evenly into the batter without leaving streaks.
Substitutions and Variations
- Peanut Butter Brookies. Drop spoonfuls of creamy peanut butter between the cookie dough and swirl lightly. Sourdough and peanut butter so perfectly together, like in my sourdough peanut butter cookies.
- Mint Brookies. Add ½ teaspoon peppermint extract to the brownie batter and top with chopped Andes mints.
- Salted Caramel Brookies. My daughter loves caramel, so obviously she loved this! Drizzle caramel sauce over the brownie layer before adding the cookie dough, then sprinkle with flaky sea salt after baking.
- Oreo Brookies. Press a layer of Oreos between the brownie and cookie layers.
- Mocha Brookies. Add 2 teaspoons espresso powder to the brownie batter.
- Brown Butter Brookies. Brown the butter for the cookie layer for a nutty, toffee flavor. I love brown butter in my blondies too!
- Swirled Brookies. Instead of layering, drop spoonfuls of both batters into the pan and swirl with a knife for a marbled look.
Holiday Sourdough Brookies
- Christmas Brookies. Use red and green M&M’s in the cookie layer, or top with holiday sprinkles right out of the oven.
- Peppermint Bark Brookies. Add peppermint extract to the brownie layer and top the cooled brookies with melted white chocolate and crushed candy canes.
- Valentine’s Day Brookies. Use pink and red sprinkles and white chocolate chips, then cut into hearts with a cookie cutter.
- Halloween Brookies. Fold candy corn M&M’s or chopped leftover Halloween candy into the cookie dough.
- Fourth of July Brookies. Top with red, white, and blue sprinkles.
Step by Step Instructions
- Step 1: Preheat the oven to 350°F and line a 9 by 13 inch pan with parchment paper, leaving an overhang on two sides so you can lift the brookies out later.
- Step 2: Whisk the melted butter with the brown sugar and granulated sugar. Add the egg, vanilla, and sourdough discard, and whisk until smooth. Stir in the flour, baking soda, and salt until just combined, then fold in the chocolate chips. Set aside while you make the brownie batter. The dough will firm up a little as it sits, which makes it easier to scoop.
- Step 3: Whisk the melted butter and sugar together. Add the eggs and vanilla and whisk vigorously for about 1 minute until the mixture is glossy and slightly lighter in color. This is the secret to a crackly brownie top! Whisk in the sourdough discard, then add the cocoa powder, flour, salt, and espresso powder. Stir until just combined and fold in the chocolate chips.
- Step 4: Pour the brownie batter into the prepared pan and spread it into an even layer. Scoop the cookie dough into small balls and drop them evenly over the brownie batter. Gently flatten each one with your fingers so the cookie dough covers most of the brownie. It’s totally fine to have little gaps where the brownie peeks through.
- Step 5: Bake for 35 to 45 minutes, until the cookie layer is golden brown and a toothpick inserted in the center comes out with moist crumbs but no wet batter. If the top is browning too quickly before the center is set, loosely tent the pan with foil for the last 10 minutes.
- Step 6: Let the brookies cool in the pan for at least 2 hours. I know it’s hard to wait, but they finish setting as they cool. For clean, bakery style squares, refrigerate for 30 minutes, then lift the brookies out using the parchment and cut into 24 squares with a sharp knife.
How to Tell When Sourdough Brookies Are Done
It can actually be really tricky to tell when the brookies are done. This is where most brookie recipes go wrong, so here’s exactly what to look for:
- The cookie layer should be evenly golden brown, not pale, especially in the center of the pan.
- The edges should look set and slightly pulled away from the sides of the pan.
- A toothpick inserted in the center should come out with moist, fudgy crumbs. Wet, shiny batter means they need more time. A completely clean toothpick means they’re slightly overbaked.
- The internal temperature should be around 190°F if you’re using an instant read thermometer.
Every oven is different, so start checking at 35 minutes.
Tips for the Best Sourdough Brookies
- Make the cookie dough first. Letting it rest while you make the brownie batter helps it firm up so it sits on top of the batter instead of sinking.
- Don’t skip the whisking step. Whisking the eggs and sugar for a full minute is what gives the brownie layer a shiny, crackly top.
- Flatten the cookie dough. Thick dough balls bake unevenly. Flattening them helps the cookie layer bake through at the same time as the brownie.
- Don’t overmix. Stir just until the flour disappears in both batters for tender brookies.
- Use a metal pan. It conducts heat better and helps everything bake evenly.
- Cool before cutting. Warm brookies are too gooey to cut cleanly. Chilling them gives you those perfect squares.
- Wipe your knife between cuts. Run it under hot water and wipe it dry for clean edges every time.
Overnight Sourdough Brookies (Optional Cold Ferment)
If you love a stronger sourdough flavor, make the cookie dough the night before, cover it, and refrigerate it for up to 24 hours. The discard has more time to develop that tangy, complex flavor. In the morning, let the dough sit at room temperature for about 15 minutes so it’s easier to scoop, then make the brownie batter and bake as directed. This is how I prep them before a party so baking day is even easier.
Troubleshooting Sourdough Brookies
- The middle is raw but the edges are done. Your oven may run hot, or you’re using a glass pan. Tent with foil and keep baking until a toothpick comes out with moist crumbs. Next time, use a metal pan and flatten the cookie dough more.
- The cookie layer sank into the brownie. The cookie dough was too warm or soft. Let it rest a little longer before scooping, or chill it for 15 minutes.
- The brownie layer is dry. They were overbaked. Start checking at 35 minutes and pull them when the toothpick shows moist crumbs.
- There are white streaks in my brookies. Your discard was too thick or not stirred in well. Stir it down well before measuring and whisk it fully into the wet ingredients.
- My brookies don’t have a crackly top. Whisk the eggs and sugar longer, about a full minute, until glossy.
How to Serve Sourdough Brookies
These are amazing on their own with a cold glass of milk, but for a special dessert, serve them warm with a scoop of vanilla ice cream and a drizzle of hot fudge. It is so good with no churn vanilla ice cream!
We call this “brookie sundae night” at our house and the kids go wild for it. They’re also perfect for bake sales, potlucks, game days, and holiday dessert trays since one pan makes 24 squares.
Storage Info
Store brookies in an airtight container at room temperature for up to 4 days. Layer parchment paper between them so they don’t stick together. For extra fudgy brookies, keep them in the fridge for up to a week. To warm one up, microwave it for 10 to 15 seconds.
How to Freeze Sourdough Brookies
Let the brookies cool completely, cut them into squares, and wrap each one in plastic wrap. Place them in a freezer bag and freeze for up to 3 months. Thaw on the counter for about an hour or microwave for 20 to 30 seconds. I keep a stash in the freezer for lunchbox treats and last minute guests.
Frequently Asked Questions
Yes! Active starter and discard both work in this recipe since the brookies get their rise from eggs and baking soda, not the starter. Just make sure your starter is a pourable, 100% hydration consistency so it mixes evenly.
Not at all. The discard adds a subtle depth of flavor that makes the chocolate taste richer, but with all the sugar and chocolate, nobody will ever guess there’s sourdough in them unless you tell them.
Yes, you can use a boxed brownie mix for the bottom layer to save time. Prepare it according to the package and stir in ¼ cup of sourdough discard, then top with the homemade sourdough cookie dough and bake as directed, checking a few minutes early.
They likely need more time in the oven. Brookies have two thick layers, so they take longer to bake than regular brownies. Look for a golden cookie top and a toothpick with moist crumbs, not wet batter, and let them cool completely since they keep setting as they cool.
You can make brookie cups in a muffin tin using the pan guide above. Traditional round brookie cookies need a thicker brownie dough, so this batter works best as bars or cups.
📖 Recipe
Sourdough Brookies
Ingredients
- ½ cup Butter Softened
- ¾ cup Brown sugar
- ¼ cup Sugar
- 1 Egg
- 1 teaspoon Vanilla extract
- ½ cup Sourdough discard
- 1 ½ cups All purpose flour
- ½ teaspoon Baking soda
- ½ teaspoon Salt
- 1 cup Semi sweet chocolate chips
For the Sourdough Brownies layer
- ¾ cup Butter Melted and cooled
- 1 ½ cups Sugar
- 3 Eggs
- 2 teaspoon Vanilla extract
- ½ cup Sourdough discard
- ¾ cup Unsweetened Cocoa Powder
- ¾ cup All purpose flour
- ½ teaspoon Salt
- 1 cup Semi Sweet Chocolate Chips
Instructions
- Preheat the oven to 350°F. Line a 9 by 13 inch metal baking pan with parchment paper, leaving an overhang on two sides.
- First, let's make the chocolate chip cookie batter. In a medium bowl, whisk the melted butter, brown sugar, and granulated sugar until combined. Add the egg, vanilla, and sourdough discard and whisk until smooth. Stir in the flour, baking soda, and salt until just combined. Fold in the chocolate chips and set aside.
- Now, it's time to make the brownie batter. In a large bowl, whisk the melted butter and granulated sugar together. Add the eggs and vanilla and whisk vigorously for about 1 minute, until glossy and slightly lighter in color. Whisk in the sourdough discard.
- Add the cocoa powder, flour, salt, and espresso powder and stir until just combined. Fold in the chocolate chips.
- Spread the brownie batter evenly in the prepared pan.
- Scoop the cookie dough into small balls and drop them evenly over the brownie batter. Gently flatten each one so the cookie dough covers most of the surface.
- Bake for 35 to 45 minutes, until the cookie layer is golden brown and a toothpick inserted in the center comes out with moist crumbs. Tent with foil for the last 10 minutes if the top is browning too quickly.
- Cool in the pan for at least 2 hours, then refrigerate for 30 minutes.
- Lift the brookies out using the parchment overhang and cut into 24 squares.
Notes
- Use 100% hydration discard straight from the fridge. Active starter works too since we aren't waiting for the starter to activate.
- You can make this ahead of time too. Make the cookie dough up to 24 hours ahead and refrigerate for a tangier flavor. Let it sit at room temperature for 15 minutes before scooping.
- If you are using a glass pan, lower the oven to 325°F and add 5 to 10 minutes.
- This makes 24 brookies, but you can make a smaller batch if necessary. Bake in an 8 by 8 or 9 by 9 inch pan for 30 to 40 minutes.
- Keep at room temperature for up to 4 days, in the fridge for up to 1 week, or frozen for up to 3 months.
