Brown Butter Sourdough Discard Brookies (Brownie and Chocolate Chip Cookie Bars)
These brown butter sourdough discard brookies are everything you love about fudgy brownies and chewy chocolate chip cookies baked into one bar. The rich, gooey brownie base gets a gut-friendly twist from sourdough discard, while the golden cookie top is packed with pools of melted chocolate and deep, nutty flavour from browned butter. They’re soft in the center, crisp on the edges, and impossible to stop eating. If you’ve never made brookies before, this is the recipe that will ruin all others for you in the best way.
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
- 8x8 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 8x8-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.