Oatmeal Chocolate Sourdough Cookie Bars are truly the best of every treat world: gooey chocolate, toothsome oats, rich butter, and a sweet-and-salty fudge layer, all brought together by a tangy swoosh of sourdough discard. These bars deliver the chew of a perfect oatmeal cookie with the decadence of a layered brownie, making them the kind of dessert you dream about sneaking from the pan. If you’ve ever looked for a way to use up extra sourdough discard—and want to impress friends and family with a bakery-worthy bar—this is it.

Oatmeal Chocolate Sourdough Cookie Bars Recipe - Recipe Image

Ingredients You’ll Need

The ingredient list for these Oatmeal Chocolate Sourdough Cookie Bars might look long, but each piece plays a starring role. From the deep caramel notes of brown sugar to the creamy richness of condensed milk, it’s a symphony that delivers unbeatable flavors and textures. Here’s what you’ll need and why:

Butter, unsalted: Adds classic cookie richness and provides the foundation for both layers; room temperature helps everything blend.
Brown sugar: Gives the bars a caramel-y chew while keeping them tender.
Granulated sugar: Balances the depth of brown sugar for perfectly sweet bars.
Egg: Binds the dough and adds softness.
Sourdough discard: Brings a subtle tang and makes the crumb extra tender—don’t skip if you love sourdough depth.
Vanilla extract: Rounds out flavor and makes everything taste like homemade comfort.
Baking soda: Helps the bars lift just the right amount as they bake.
Salt: Essential to balance all that sweetness—don’t underestimate its magic touch.
All-purpose flour: The sturdy base that keeps everything together, with just the right density.
Rolled oats: Adds texture and a nostalgic cookie flavor you can’t resist.
Coconut flakes: A hint of tropical nuttiness that complements both chocolate and oats.
Chocolate chunks or chips: Use your favorite for bursts of melty chocolate throughout.
Sweetened condensed milk: The secret to a luscious, fudgy middle.
Extra chocolate chips: For the indulgent chocolate fudge layer that makes these bars stand out.
Extra butter: Enriches the fudge layer, giving it melt-in-your-mouth appeal.
Extra salt: Heightens all the flavors, especially in the chocolate fudge swirl.

How to Make Oatmeal Chocolate Sourdough Cookie Bars

Step 1: Cream Butter and Sugars

Start by beating together your room-temperature butter, brown sugar, and granulated sugar until the mixture is light and fluffy. A stand mixer or hand beaters really helps here. Taking the time to cream these well not only builds structure for the bars but also gives them that signature bakery-style texture.

Step 2: Add Egg, Sourdough Discard, and Vanilla

Crack in the egg, then add your sourdough discard and vanilla extract. Beat until smooth and fully combined. The sourdough discard slips in seamlessly; it won’t taste “sour” but will add subtle complexity.

Step 3: Mix in Dry Ingredients

Sprinkle in the baking soda, salt, rolled oats, and flour. Mix until no flour streaks remain. This step transforms the dough into that irresistible oatmeal cookie base we love.

Step 4: Fold in Chocolate Chunks and Coconut

Stir in chocolate chunks (or chips) and coconut flakes. Now is also the moment to add any extra goodies (chopped nuts, dried fruit) if you’re feeling creative. Every bite of these Oatmeal Chocolate Sourdough Cookie Bars holds a surprise!

Step 5: Optional Fermentation for Deeper Flavor

If you’re feeling patient, refrigerate the dough for 12 to 48 hours. This slow ferment deepens the flavors and gives the bars a subtle tang, thanks to the sourdough. Just remember to let the dough warm up for about 30–60 minutes before pressing it into the pan. Or, if you’re short on time, skip ahead and bake right away.

Step 6: Prepare the Pan and Layer the Dough

Line a 9×9 inch baking pan with parchment paper for easy bar removal. Gently press two-thirds of the oatmeal cookie dough into the bottom, making an even layer. This forms the delicious, hearty foundation.

Step 7: Create the Fudge Chocolate Layer

In a small saucepan over low to medium heat, melt extra butter, chocolate chips, and sweetened condensed milk, stirring constantly until the mixture is silky smooth—don’t let it scorch. Finish by stirring in a pinch of salt for extra flavor dimension.

Step 8: Assemble and Top

Pour your warm fudgy chocolate layer over the pressed cookie dough. Tear off pieces of the remaining dough and sprinkle them across the top. Add a sprinkle of flaky sea salt, if desired, for a bakery-style touch.

Step 9: Bake

Bake the Oatmeal Chocolate Sourdough Cookie Bars at 350°F (175°C) for 30–35 minutes, until the top is golden and the center is just set. Your kitchen will smell like pure heaven!

Step 10: Cool, Slice, and Enjoy

Let the bars cool completely before cutting—this gives the fudge layer time to set and makes slicing clean and easy. Now gather everyone and dig in!

How to Serve Oatmeal Chocolate Sourdough Cookie Bars

Garnishes

A little finishing touch can make these bars feel truly special. Try a flourish of flaky sea salt right after baking, or a dusting of powdered sugar before serving. Even a drizzle of melted white chocolate or caramel can elevate each square into a showstopper.

Side Dishes

Pair your Oatmeal Chocolate Sourdough Cookie Bars with a cup of freshly brewed coffee, a cold glass of milk, or a scoop of your favorite vanilla or coconut ice cream. They’re also divine with a fruity compote or yogurt if you’re feeling fancy at brunch.

Creative Ways to Present

Cut the bars into bite-sized squares and stack them on a pedestal for parties, or serve warm topped with a dollop of whipped cream for a rustic dessert. You can even assemble a “cookie bar sundae” station where everyone customizes their own treat with toppings such as toasted coconut, berries, or more chocolate chips.

Make Ahead and Storage

Storing Leftovers

Once your Oatmeal Chocolate Sourdough Cookie Bars are completely cooled, store them in an airtight container at room temperature for up to three days. This keeps them moist and the fudge layer deliciously soft.

Freezing

These bars freeze beautifully! Place cut squares in a single layer on a baking sheet, freeze until solid, then transfer to a ziptop bag or airtight container. They’ll last in the freezer for up to three months—perfect for emergency dessert cravings.

Reheating

To enjoy that just-baked freshness, pop a bar in the microwave for 10–15 seconds. The chocolate fudginess returns, the coconut becomes fragrant again, and the whole treat feels like it just came out of the oven.

FAQs

Can I make Oatmeal Chocolate Sourdough Cookie Bars without sourdough discard?

Absolutely! While the sourdough discard adds unique tang and texture, you can substitute with yogurt or buttermilk in a pinch—just use the same amount. The flavor will still be delicious, though a little less complex.

Do I have to chill the dough, or can I bake right away?

Chilling is optional but highly recommended for depth of flavor and improved texture. If you’re impatient or pressed for time, go ahead and bake straight after mixing; the bars will still turn out tender and tasty.

What’s the best way to cut clean squares?

Let the bars cool completely, then run a large sharp knife under hot water, wipe dry, and slice through in one motion. For extra tidy edges, wipe the knife clean between each cut.

Can I make these gluten-free?

Yes! Swap the all-purpose flour for your favorite 1-to-1 gluten-free blend, and double-check your oats are certified gluten-free. The rest of the recipe remains the same, and the bars still turn out beautifully chewy.

Can I use different mix-ins?

Definitely. Oatmeal Chocolate Sourdough Cookie Bars are endlessly adaptable—try swapping coconut for chopped walnuts, adding dried cherries, or using peanut butter chips. Make it your own and use up whatever you love.

Final Thoughts

If you’ve never tried baking with sourdough discard, these Oatmeal Chocolate Sourdough Cookie Bars are the tastiest way to start. Make a batch for your next get-together—or just for yourself! I have a strong feeling you’ll fall head over heels for every gooey, chocolatey, oat-studded bite.