Why These Fudgy Chocolate S’more Cookie Bars Are a Must-Try

After the immense popularity of my original s’more cookie bars recipe, I knew I had to take it up a notch with a rich chocolate version. These bars aren’t just good; they’re absolutely fantastic. Here are a few reasons why they’ll quickly become your new favorite dessert:

1. Remarkably Thick & Fudgy: I’m a firm believer that a truly great cookie bar should be thick and substantial. This recipe delivers exactly that. The robust cookie dough creates a bar that holds its shape beautifully, making for clean, satisfying cuts without crumbling. Unlike some brownies that can be delicate, these cookie bars maintain their integrity from pan to plate.
2. A Symphony of Textures: The magic of s’mores lies in their contrasting textures, and these bars capture it perfectly. You get the delightful crunch of the graham cracker base, the rich, melt-in-your-mouth fudginess of the chocolate cookie dough (using the same amazing base as my fudgy cosmic brownie cookies), and the incredibly gooey, soft chew of perfectly toasted marshmallows. Every bite is an experience!
3. Visually Stunning Layers: There’s something inherently satisfying about a dessert with distinct, gorgeous layers. These s’more cookie bars are a feast for the eyes as well as the palate, with clearly defined layers that promise a complex and delicious treat before you even take the first bite. They’re perfect for impressing guests or simply enjoying a beautiful homemade creation.
4. Deceptively Easy to Make: Don’t let their impressive appearance fool you – these layered treats are surprisingly simple to whip up. The process is straightforward: line a pan with graham crackers, press in the decadent cookie dough, and top with marshmallows. Even if you’re new to baking, you’ll find this recipe incredibly approachable and rewarding.

Essential Ingredients for Fudgy S’more Cookie Bars & Substitutions

Getting the perfect texture and flavor for these chocolate s’more cookie bars starts with quality ingredients. Here’s a closer look at what you’ll need and some helpful notes:

• Cocoa Powder: For a deep, moist, and intensely rich flavor that truly mimics a brownie, I highly recommend using Hershey’s Special Dark Cocoa Powder. While you can substitute it with regular unsweetened cocoa powder, be aware that your bars will likely have a slightly puffier, less dense texture and a milder chocolate flavor, rather than the iconic fudgy brownie taste we’re aiming for.
• Light Corn Syrup: This ingredient is key to achieving that signature chewy, dense, and wonderfully fudgy texture. A small amount goes a long way! It’s crucial to understand that light corn syrup is **not** the same as high-fructose corn syrup, so don’t be alarmed by its inclusion. You can typically find Karo or generic brands in the baking aisle. If corn syrup is unavailable or you prefer not to use it, a thick honey can be used as a substitute to yield a similar chewy texture, though it may subtly alter the flavor.
• Graham Crackers: For that quintessential s’mores flavor, I personally find Honey Maid brand to be the best choice. However, any generic brand will work just fine. You’ll need approximately 16 full-sized graham cracker squares, which usually means about two sleeves from a standard box.
• Mini Marshmallows: These are essential for the classic s’mores experience. You’ll need one standard 10-ounce bag to generously top your bars. Mini marshmallows melt and toast beautifully under the broiler, creating that irresistible gooey layer.

Make it Gluten-Free! Adapting this recipe for a gluten-free diet is simple. Just swap your regular all-purpose flour for your favorite gluten-free 1-to-1 baking flour blend and ensure your graham crackers are also gluten-free. Many bakers have found success using Bob’s Red Mill Gluten Free 1-to-1 Baking Flour in similar base dough recipes (like the cosmic brownie cookies mentioned earlier), with excellent results. Always double-check all other ingredients to confirm they are certified gluten-free.

Step 1: Prepare the Rich Chocolate Cookie Dough

1. In a large mixing bowl, combine the softened **unsalted butter** (¾ cup, or 1 ½ sticks), **light brown sugar** (¾ cup), and **granulated sugar** (¾ cup). Using an electric mixer on medium-high speed, cream these ingredients together for a full 2 minutes until the mixture becomes light, fluffy, and noticeably pale. This step incorporates air, contributing to the bar’s texture.
2. Next, add the **2 large eggs**, **2 teaspoons of vanilla extract**, and **3 tablespoons of light corn syrup**. Mix on low speed until all ingredients are just combined. It’s important not to overmix at this stage. Stop the mixer and use a spatula to scrape down the sides of the bowl, ensuring everything is thoroughly incorporated for a consistent dough.
3. Introduce the leavening and seasoning by adding **1 teaspoon of baking powder** and **½ teaspoon of salt**. Mix for an additional 5-10 seconds until these dry ingredients are evenly distributed throughout the wet mixture.
4. Finally, add the dry components: **¾ cup of dark cocoa powder** and **2 ¼ cups of all-purpose flour**. Mix on medium speed until the flour and cocoa are just combined into a cohesive dough. Be careful not to overmix, as this can lead to tough bars.

Tip: This cookie dough is quite thick, making a stand mixer ideal for the job. If you’re using a handheld mixer, you might find it helpful to finish mixing in the flour by hand with a sturdy spatula to ensure everything is evenly incorporated without overworking the dough.

Step 2: Prepare the Pan & Press in the Cookie Dough

1. Preheat your oven to 350°F (175°C). Lightly spray a light-colored metal 9×13 inch baking pan with cooking spray. Then, line the pan with two pieces of parchment paper. Arrange the parchment so that it covers the bottom and extends up the long sides, leaving a generous 2-inch overhang on each side. This “sling” will make it incredibly easy to lift the entire batch of bars out of the pan once cooled.
2. Arrange a single layer of graham crackers across the bottom of the prepared pan. You’ll need roughly 16 squares, breaking them as needed to fit snugly and cover the entire base. This forms the crunchy foundation of your s’mores bars.
3. To evenly distribute the cookie dough, drop it into small, manageable chunks all over the graham cracker base. This method is much easier than trying to spread one large mass of thick dough. Once all the dough has been added, use a clean spatula or your hands to gently but firmly press the dough down into an even, smooth layer, making sure to reach into all the corners of the pan. Be mindful not to shift the graham cracker base too much during this process.

Tip: If your chocolate cookie dough feels a bit sticky, try spraying your hands lightly with cooking spray or placing another piece of parchment paper directly on top of the dough before pressing down. This will prevent sticking and help you achieve a perfectly smooth, even layer.

Step 3: Bake the Cookie Base

1. Place the pan in your preheated 350°F (175°C) oven and bake for 18-22 minutes. The bars are ready when the center no longer looks wet and appears set. It’s okay if the center seems slightly underdone; the residual heat from the hot pan will continue to cook them as they cool, ensuring a perfectly fudgy result. Overbaking can lead to dry bars, so err on the side of caution!
2. As soon as the bars come out of the oven, immediately proceed to the next step to add the marshmallows. Timing is key here for optimal marshmallow melting and toasting.

Step 4: Top with Marshmallows & Broil to Golden Perfection

1. Immediately after removing the baked cookie bars from the oven, generously sprinkle the entire 10-ounce bag of mini marshmallows over the hot surface. The heat from the bars will start to soften them.
2. Turn on your oven’s “BROIL” function. Place the pan on the bottom or middle rack, ensuring there’s enough distance from the broiler element to prevent burning. **This is crucial: stand by the oven and watch it very, very closely – do not walk away!** Marshmallows can go from perfectly golden to burnt in a matter of seconds. As soon as you notice a light golden brown color developing, rotate the pan to ensure even toasting and prevent any hot spots from charring the marshmallows. Remove the pan from the oven as soon as the marshmallows are beautifully golden brown and lightly caramelized.

Step 5: Add Optional Toppings for Extra Indulgence!

For an extra layer of classic s’mores flavor and a beautiful finish, consider adding optional toppings immediately after broiling. Press pieces of Hershey’s milk chocolate bar and additional graham cracker crumbs or pieces onto the warm, toasted marshmallows. I highly recommend using at least one, if not two, standard Hershey bars (I used one in the photos but would definitely opt for two next time!). The melting milk chocolate on top perfectly balances the sweetness of the marshmallows and enriches that authentic s’mores taste. You could also sprinkle some milk chocolate chips for a similar effect.

Step 6: Cool, Chill, and Cut into Perfect Squares

Patience is key for the best results! Before attempting to cut these fudgy delights, allow the pan to cool completely at room temperature. Once cooled, transfer the pan to the refrigerator for at least 30-60 minutes. This chilling step is essential as it helps the chocolate firm up and the marshmallows set, allowing for incredibly clean and precise cuts. Using the parchment paper overhang, you can easily lift the entire slab of bars out of the pan onto a cutting board for easier slicing.

Want to achieve super clean, bakery-style cuts every time? For this month’s baking challenge, I’ve put together a cool interactive slideshow complete with video tips specifically on how to cut these bars cleanly. It’s a must-watch for perfect presentation!

S’more Cookie Bar Tips & Variations

Once you’ve mastered the basic recipe, feel free to get creative with these delicious bars!

• Experiment with Toppings: While Hershey bars are classic, don’t limit yourself! You can top these bars with a variety of additions: try mini chocolate chips, chopped candy bars (like Reese’s for a peanut butter twist, or Snickers), M&Ms, or even a sprinkle of sea salt to enhance the chocolate flavor. A dusting of **graham cracker crumbs** adds extra texture.
• Switch Up the Graham Crackers: For a deeper chocolate flavor right from the base, consider using chocolate graham crackers instead of the traditional honey variety. This adds another layer of cocoa goodness that chocolate lovers will adore.
• Add a Peanut Butter Swirl: For an extra rich and decadent flavor, warm up some creamy peanut butter until pourable and drizzle it over the baked cookie base *before* adding the marshmallows. Allow the bars to cool for about 20 minutes first to prevent the peanut butter from soaking entirely into the cookie layer. Then, proceed with adding and broiling the marshmallows as directed.
• Don’t Overbake the Cookie Base: Remember, the cookie dough will continue to cook slightly as it cools in the hot pan. An ever-so-slightly underbaked center will yield the fudgiest results.
• Use a Good Quality Pan: A light-colored metal pan helps conduct heat evenly, preventing the edges from getting too dark before the center is cooked through.

Frequently Asked Questions: