Brown Butter Sourdough Discard Brookies (The Best Brownie-Cookie Bars)
If you’ve ever stood in front of your kitchen counter debating whether to make brownies or cookies, this recipe is for you. These brown butter sourdough discard brookies combine the best of both: a fudgy, chocolate-rich brownie base layered with golden, gooey chocolate chip cookie dough. Each bite is indulgent, rich, and a little over-the-top (in the best way), with a subtle tang from sourdough discard and the nutty complexity that only browned butter can bring.
It’s the kind of recipe you’ll want to make for friends, but it might also be the one you end up hoarding in the freezer, eating cold when no one’s looking (we have all been there). This is especially true for those brown butter brookies.
Why You Will Love These Brown Butter Sourdough Discard Brookies
These brookies hit that perfect balance between chewy and gooey. The sourdough discard adds depth without overpowering, while the brown butter brings a rich, toffee-like flavor that cuts through the sweetness. The brownie base is soft and dense, and the cookie top bakes up golden and slightly crisp around the edges. If you’re a texture person, this is your dream combo and it’s ideal when making brown butter sourdough discard brookies.
What Brown Butter Does in Baking
If you’ve never browned butter before, let me talk you into it. Browning butter is one of those small steps that makes a huge difference. It gives your bakes this rich, nutty, toffee-like flavor that you just can’t get from regular melted butter. In this recipe, it takes the cookie dough from good to unreal, especially in our brown butter sourdough discard brookies.
To make brown butter, all you need is a saucepan and some patience. Start by adding your salted butter to a small or medium-sized saucepan over medium heat. As it melts, it’ll start to bubble and foam that’s totally normal. Stir it occasionally and keep an eye on the color. After a few minutes, you’ll see little golden-brown bits forming at the bottom of the pan and you’ll start to smell this warm, nutty aroma. That’s when it’s ready. Immediately remove it from the heat so it doesn’t burn and pour it into a heat-safe bowl to cool slightly before using it in your dough or batter. The smell is irresistible when making these brookies.
Once you’ve browned butter once, you’ll want to use it in everything—and honestly, I support that. (I add it to EVERYTHING)
Why Add Sourdough Discard to These Brown Butter Sourdough Discard Brookies?
Sourdough discard isn’t just a way to reduce food waste, it’s also a magical secret weapon in baking. When added to sweet recipes, it gives just a hint of tang that balances out the sugar and adds complexity. In these brookies, it adds moisture and softness to the brownie layer, making it melt-in-your-mouth fudgy without being too dense. You can use either unfed or active sourdough discard here, depending on what you have to make these delightful brown butter sourdough brookies.
How to Store Brown Butter Sourdough Discard Brookies
Once cooled, these brookies store beautifully. Keep them in an airtight container at room temperature for up to three days, though good luck making them last that long. For longer storage, you can refrigerate them for up to five days or freeze individual slices in a sealed container. I highly recommend reheating them in the microwave for 10–15 seconds before eating. It brings back that soft, gooey center and makes the chocolate even more melty and rich, just like they are initially with brown butter sourdough discard brookies.
Brown Butter Sourdough Discard Brookies (Brownie and Chocolate Chip Cookie Bars)
Equipment
- Medium saucepan (for browning butter for both layers)
- Four mixing bowls (two for each layer: one for wet ingredients and one for dry)
- Whisk or spoon
- Rubber spatula (for folding and scraping)
- Measuring cups and spoons
- 8×8 inch baking pan
- Parchment paper (optional but helpful for easy removal)
Ingredients
Brownie Layer:
- 113 g 1/2 cup salted butter, browned
- 200 g 1 cup granulated sugar
- 100 g 1/2 cup brown sugar
- 1 large egg
- 1 tsp vanilla extract
- 120 g 1/2 cup sourdough discard (unfed or active)
- 75 g 3/4 cup cocoa powder
- 45 g 1/3 cup all-purpose flour
- 1/2 tsp baking powder
- 1/2 tsp salt
- Optional: 85g 1/2 cup dark chocolate chunks or chips
- Optional: Maldon flaky sea salt for topping
Cookie Dough Layer:
- 113 g 8 tbsp salted butter, browned and cooled
- 100 g 1/2 cup white sugar
- 50 g 1/4 cup packed light brown sugar
- 1 tsp vanilla extract
- 1 large egg
- 190 g 1 1/2 cups all-purpose flour
- 1/2 tsp baking soda
- 1/4 tsp salt
- 130 g 3/4 cup chocolate chips
- Optional: 1–2 tbsp milk only if dough is dry
Instructions
Brown the butter:
- Brown the butter separately for the brownie batter and cookie dough. Set aside each to cool slightly before using.
Make the Brownie Batter:
Mix the wet ingredients:
- In a large bowl, whisk together the browned butter, granulated sugar, brown sugar, egg, vanilla extract, and sourdough discard until smooth.
Combine the dry ingredients:
- In a separate bowl, whisk together the cocoa powder, flour, baking powder, and salt.
Combine wet and dry:
- Add the dry ingredients to the wet mixture and stir until just combined. Fold in chocolate chunks or chips if using. Set aside.
Make the Cookie Dough:
Mix the wet ingredients:
- In another bowl, stir together the browned butter, granulated sugar, brown sugar, egg, and vanilla extract.
Combine the dry ingredients:
- In a separate bowl, whisk together the flour, baking soda, and salt.
Combine wet and dry:
- Add the dry ingredients to the wet and stir until a soft dough forms. Fold in chocolate chips. If the dough feels dry or crumbly (from browning the butter), add 1–2 tablespoons of milk to help bring it together.
Assemble the brookies:
- Line an 8×8-inch pan with parchment paper or grease your pan.
- Spread half of the brownie batter evenly into the bottom of the pan.
- Add small spoonfuls of cookie dough over the brownie layer and gently press them into the batter to create a marbled middle layer.
- Pour the remaining brownie batter over top and smooth it out with a spatula.
- Drop the rest of the cookie dough over the top in clumps. Do not press it flat. Let it bake naturally for that layered brookie look.
Bake:
- Bake at 350°F (175°C) for 30 to 35 minutes or until the cookie top is golden and a toothpick inserted into the center comes out with a few moist crumbs but no raw batter.
Cool and serve:
- Let the brookies cool completely before slicing. They will continue to set as they cool.
- Sprinkle with flaky sea salt if desired.
Don’t have a sourdough starter? No Problem! Check out my beginner-friendly sourdough starter guide.
Having trouble with your sourdough starter? Here are some ways to troubleshoot to get a super strong sourdough starter!
Need to stock up on sourdough essentials? Check out my sourdough must haves!
More Recipes You Have To Try!
- Lemon Blueberry Sourdough
- Jalapeño Cheddar Sourdough
- S’mores Sourdough
- Sourdough Bagels
- Original Bread Recipe
- Banana chocolate chip muffins (sourdough discard)
- Same Day Sourdough Discard Cinnamon Buns with Brown Butter Frosting
- Brown Butter Sourdough Discard Brownies
- Easy Chocolate Sourdough Bread Recipe
