Sourdough S’mores Cookie Bars
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If you’re looking for a fun way to use up your sourdough discard, these sourdough s’mores cookie bars are a delicious summer dessert that comes together fast! Perfect for grill-outs, Fourth of July celebrations, or other summer parties, they are reminiscent of the classic summer treat, but in cookie bar form!
The only thing easier than baking cookies is baking cookie bars. You literally just plop all that cookie dough in a pan and bake it. It’s remarkable. Remarkably simple. 🙂
I love this recipe because I love chocolate, gooey marshmallows, and graham crackers. When I’m sitting around a fire with family, I’m the one eating multiple s’mores with the kiddos. I just *love* them!
The steps are simple, and I’ll walk you through all of them. Let’s get into it below!
Looking for more sourdough discard dessert recipes? Check these out!
- sourdough sugar cookie bars
- sourdough s’mores cookies
- sourdough brown butter chocolate chip cookies
- sourdough millionaire’s shortbread
Step-By-Step Instructions
Preheat your oven to 350°F (177°C). Line a 9×9-inch baking pan with parchment paper and set aside.
In a medium bowl, whisk together the flour, crushed graham crackers, baking soda, and salt.
In a large mixing bowl, beat the softened butter, brown sugar, and granulated sugar until light and fluffy.
Mix in the eggs, vanilla extract, and sourdough discard until smooth and combined.
Chop the Hershey’s bars.
Add the dry ingredients and mix just until combined. Fold in the chopped Hershey’s chocolate and chocolate chips.
Press about two-thirds of the cookie dough evenly into the bottom of the prepared baking pan.
Arrange the marshmallows in an even layer over the cookie dough.
Drop spoonfuls of the remaining cookie dough over the marshmallows. Gently press down slightly, leaving some marshmallows visible.
Bake for 25–32 minutes, or until the bars are golden brown and cooked through.
About 5 minutes before the bars are done baking, sprinkle the remaining crumbled Hershey’s chocolate bar over the top.
Return the pan to the oven and bake for the remaining 5 minutes until the chocolate is melted.
Let the bars cool completely in the pan. Lift them out using the parchment paper and slice into 16 squares.
Helpful Tips for the BEST Sourdough S’mores Cookie Bars
1. Use Room Temperature Butter
Softened butter creams more easily with the sugars, creating a thick and chewy cookie dough. Butter that is too cold won’t mix properly, while melted butter can make the bars spread too much.
2. Don’t Overmix the Dough
Mix the dry ingredients into the wet ingredients just until combined. Overmixing can develop too much gluten and lead to dense cookie bars instead of soft, chewy ones.
3. Leave Some Marshmallows Exposed
When adding the top layer of dough, don’t worry about completely covering the marshmallows. Leaving some visible creates those classic gooey, toasted s’mores pockets throughout the bars.
4. Add the Final Chocolate at the End
Sprinkling the remaining Hershey’s chocolate over the bars during the last 5 minutes of baking keeps it soft and melty. If added at the beginning, the chocolate can sink into the dough and lose that signature s’mores look.
5. Let the Bars Cool Before Slicing
The marshmallows and chocolate will be very gooey straight from the oven. Allow the bars to cool completely before cutting for cleaner slices and the perfect chewy texture.
Equipment
- 9×9-inch baking pan
- Parchment paper
- Large mixing bowl
- Medium mixing bowl
- Hand mixer or stand mixer
- Measuring cups and spoons
- Kitchen scale (optional, for metric measurements)
- Rubber spatula
- Whisk
- Sharp knife for slicing
- Cooling rack
Storage Instructions
- Store leftover Sourdough S’mores Cookie Bars in an airtight container at room temperature for up to 4 days.
- For longer storage, refrigerate the bars in an airtight container for up to 1 week.
- To enjoy them warm, microwave an individual bar for 10–15 seconds to soften the marshmallows and melt the chocolate.
- Freeze cooled bars in a freezer-safe container or zip-top bag for up to 3 months. Place parchment paper between layers to prevent sticking.
- Thaw at room temperature for several hours before serving.
Ingredients
Cookie Dough
- 2 1/4 cups all-purpose flour 280 g
- 1/4 cup roughly crushed graham crackers 30 g, about 4 graham cracker sheets
- 1 1/2 teaspoons baking soda 7 g
- 1/4 teaspoon salt 1.5 g
- 1 cup salted butter room temperature (227 g)
- 3/4 cup brown sugar 165 g
- 3/4 cup granulated sugar 150 g
- 2 large eggs
- 1 teaspoon vanilla extract 5 g
- 1/2 cup sourdough discard 120 g
- 2 Hershey’s chocolate bars roughly chopped (about 85 g)
- 3/4 cup semi-sweet chocolate chips 130 g
Filling & Topping
- 23 regular-sized marshmallows
- 1 Hershey’s chocolate bar roughly crumbled (about 45 g)
Instructions
Step 1: Prepare the Pan
- Preheat the oven to 350°F (177°C).
- Line a 9×9-inch baking pan with parchment paper, allowing some overhang on the sides for easy removal.
Step 2: Mix the Dry Ingredients
- In a medium bowl, whisk together the flour, crushed graham crackers (bigger pieces are just fine. they add texture), baking soda, and salt. Set aside.
Step 3: Make the Cookie Dough
- In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy, about 2–3 minutes.
- Add the eggs one at a time, mixing well after each addition. Mix in the vanilla extract and sourdough discard until fully incorporated.
- Gradually add the dry ingredients and mix just until combined.
- Fold in the chopped Hershey’s chocolate bars (2 bars) and the chocolate chips.
Step 4: Assemble the Bars
- Press approximately two-thirds of the cookie dough evenly into the bottom of the prepared pan.
- Arrange the marshmallows in a single layer over the dough, using about 22–25 marshmallows to cover most of the surface.
- Using the remaining one-third of the cookie dough, scoop small portions over the marshmallows. Gently press the dough down slightly, leaving some marshmallows partially visible. The marshmallows do not need to be completely covered.
Step 5: Bake
- Bake for 25–32 minutes, or until the bars are golden brown and the cookie dough is fully baked through.
- About 5 minutes before the bars are finished baking, remove the pan from the oven and sprinkle the remaining crumbled Hershey’s chocolate bar evenly over the top.
- Return the pan to the oven and bake for the remaining 5 minutes, allowing the chocolate to melt into the bars.
Step 6: Cool and Slice
- Allow the bars to cool completely in the pan before lifting them out using the parchment paper overhang.
- Slice into 16 squares and serve.
Nutrition
