Sourdough chocolate chip cookie bars use unfed sourdough starter to add a light tang and a soft, chewy texture to a classic pan of cookie bars.
They are a smart way to use discard starter, and they come together in one bowl with melted butter. The bars have crisp edges, a thick chewy center, and plenty of melted chocolate and walnuts.
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Why This Sourdough Chocolate Chip Cookie Bars Recipe Works
Sourdough starter adds moisture and a gentle tang that balances the brown sugar. The tang is subtle, so the bars taste like a deeper, more interesting version of a classic cookie.
Melted butter and brown sugar create a chewy, fudgy center, while the granulated sugar helps the edges turn crisp and golden.
Baking the dough in a 9×13 inch pan makes the bars thick and even, and they cut into neat squares once cooled.
Ingredients for Sourdough Chocolate Chip Cookie Bars
- 1 cup unfed sourdough starter, at room temperature
- 3/4 cup unsalted butter, melted
- 1 cup packed brown sugar
- 1/2 cup granulated sugar
- 2 large eggs
- 2 teaspoons vanilla extract
- 2 1/4 cups all purpose flour
- 1 teaspoon baking soda
- 1/2 teaspoon kosher salt
- 2 cups chocolate chips or chunks
- 1 cup chopped walnuts, optional
Sourdough starter. Use discard at room temperature so it mixes smoothly. It adds tang and moisture and does not need to be bubbly.
Melted butter. Butter adds richness and makes the bars chewy. Cool it for a few minutes so it does not scramble the eggs.
Brown sugar. It brings molasses flavor and keeps the center soft and chewy.
Chocolate chips. Use semisweet or dark chunks. Larger pieces give puddles of melted chocolate.
Walnuts. Walnuts add crunch. Skip them if you prefer smooth bars, or use pecans instead.
How to Make Sourdough Chocolate Chip Cookie Bars
1. Heat the oven Heat the oven to 350 degrees F and line a 9×13 inch pan with parchment paper, leaving an overhang for lifting.
2. Mix the sugars and butter In a large bowl, stir the melted butter, brown sugar, and granulated sugar until combined and smooth.
3. Add the eggs and vanilla Whisk in the eggs and vanilla until the mixture looks glossy, then stir in the sourdough starter.
4. Mix the dry ingredients In a separate bowl, whisk the flour, baking soda, and salt together.
5. Combine the batter Add the dry ingredients to the wet mixture and stir until just combined, with no dry flour left.
6. Add the mix ins Fold in the chocolate chips and walnuts if using.
7. Fill the pan Spread the dough into the pan with a spatula and press it into an even layer to the corners.
8. Bake the bars Bake for 25 to 30 minutes, until the edges are golden and a toothpick in the center comes out with a few moist crumbs.
9. Cool and cut Cool in the pan for 10 minutes, then lift out with the parchment, cool completely, and cut into 24 bars.
How to Serve Sourdough Chocolate Chip Cookie Bars
Cut the bars into squares and serve them slightly warm with a scoop of vanilla ice cream, or at room temperature with cold milk. They also sit nicely on a dessert table with fudgy chocolate brownies, thick bakery style cookies, peanut butter cookie bark, and no bake dough bars.
How to Store and Reheat Sourdough Chocolate Chip Cookie Bars
Store the bars in an airtight container at room temperature for up to 4 days. Freeze the cut bars, wrapped tightly, for up to 3 months and thaw them at room temperature. Warm a bar in the microwave for 10 seconds to revive the soft center.
Tips and Variations for Sourdough Chocolate Chip Cookie Bars
Cool the butter. Hot butter can melt the chocolate chips and cook the eggs, so let it rest for 5 minutes.
Use room temperature starter. Cold starter stiffens the butter and makes the dough lumpy.
Line the pan. Parchment makes it easy to lift the bars out and cut clean squares.
Underbake slightly. Pull the pan when the center still looks a touch soft. It sets as it cools.
Press chips on top. Press a handful of chocolate chips onto the surface right after baking for a bakery look.
Use bread flour. Swap bread flour for the all purpose flour for chewier bars.
Skip the raw dough. Do not taste the raw dough, since it contains raw egg and flour.
Cool leftovers. Let the bars cool fully before storing so steam does not make them soggy. For general leftover guidance, see the University of Minnesota Extension guide to storing leftovers.
Frequently Asked Questions About Sourdough Chocolate Chip Cookie Bars
Can I use active starter in sourdough chocolate chip cookie bars?
Yes. Active starter works too and adds a little more lift, though discard gives the same flavor and a denser chew.
How do sourdough chocolate chip cookie bars taste?
They taste like classic cookie bars with a mild tang that balances the sweetness and brings out the chocolate.
Can I freeze sourdough chocolate chip cookie bars?
Yes. Wrap the cut bars tightly and freeze them for up to 3 months. Thaw at room temperature.
Can I leave out the walnuts?
Yes. Replace them with an extra 1/2 cup of chocolate chips or leave the dough as it is.
How do I cut clean bars?
Cool the pan completely, lift the bars out with the parchment, and cut with a sharp knife wiped clean between cuts.
Sourdough Chocolate Chip Cookie Bars with Walnuts
Equipment
- 9×13-inch baking pan
- Parchment paper
- Mixing bowls
- Whisk
- Spatula
- Wire rack
Ingredients
Main Ingredients
- 1 cup unfed sourdough starter at room temperature
- ¾ cup unsalted butter melted
- 1 cup brown sugar packed
- ½ cup granulated sugar
- 2 large eggs
- 2 tsp vanilla extract
- 2 ¼ cup all purpose flour
- 1 tsp baking soda
- ½ tsp kosher salt
- 2 cup chocolate chips or chunks
- 1 cup walnuts chopped, optional
Instructions
Cooking
- Prep. Heat the oven to 350 degrees F and line a 9×13 inch pan with parchment paper.
- Make the dough. Stir the melted butter and both sugars, whisk in the eggs and vanilla, then add the starter.
- Add flour and chocolate. Stir in the flour, baking soda, and salt until just combined, then fold in the chocolate and walnuts.
- Bake. Press the dough into the pan and bake for 25 to 30 minutes, until the edges are golden.
- Cool. Cool for 10 minutes, lift out, cool completely, and cut into 24 bars.
