S’mores Cookie Bars with Brown Butter and Toasted Marshmallows
If you’re anything like us, then your dream summer includes gooey marshmallows, melty milk chocolate, and the nostalgic flavor of graham crackers. The wondrous trio that makes up s’mores. These S’mores Cookie Bars celebrate the classic flavors, and introduce a fourth teammate, brown butter cookie dough. They’ve got everything you love about a campfire s’more, plus they’re baked into a rich, chewy cookie bar. And yes, we broil the top layer of marshmallows until perfectly golden for that extra toasty finish. No fire pit required. Some things are better together, and s’mores + cookie is one of those things.
Why You’ll Love These Bars
- Rich, buttery flavor from brown butter. Browning the butter first may seem like it’s a little extra, but trust us. The nutty, toasty, brown butter flavor makes these cookie bars taste even more like regular s’mores.
- Real graham crackers folded into the dough for texture and flavor. You can’t have s’mores without graham crackers. We break up graham crackers into bite-sized pieces and fold them into the cookie dough, giving these bars a subtle graham cracker flavor.
- Classic, melty milk chocolate that tastes like childhood and summer. We strongly believe that to make the best s’mores, you need to use classic Hershey’s chocolate bars, the ones you grew up eating as a kid.
- A layer of mini marshmallows inside and on top. S’mores aren’t s’mores without toasted marshmallows, and these give the cookie bars amazing gooey texture and that signature toasted look.
- No campfire needed. No need to build a fire for these! Just bake the bars in the oven and finish with a quick broil to toast the marshmallows.
What Are S’mores Cookie Bars?
S’mores are a classic American dessert consisting of milk chocolate squares and toasted marshmallows sandwiched between two graham crackers. They’re called “s’mores” because once you’ve tasted them, you’ll definitely want “some more.” To make traditional s’mores, you take half of a graham cracker sheet and place 2 squares of Hershey’s chocolate on top (it’s gotta be Hershey’s to be traditional). Then, you skewer a marshmallow and roast it over an open flame, getting it browned on the outside and melty on the inside, before placing it on top of the chocolate and covering it with another half of a graham cracker sheet. The hot marshmallow melts the chocolate, making a gooey, delicious mess.
S’mores cookie bars are basically what they sound like. A thick, bar cookie that’s baked as a sheet and stuffed and topped with s’mores ingredients to make them resemble the classic dessert. The cookie bars have a different structure than a typical s’more, but they have all of the same nostalgic flavors and gooeyness, plus the taste of a perfect brown butter cookie.
Ingredients in These Bars
- Flour – all-purpose flour is best here.
- Butter – use unsalted butter as it works best for browning. For more information about how to make brown butter, check out our recipe for brown butter Kitchen Sink Cookies.
- Eggs – for best results, use eggs that are at room temperature (leave them on the counter for a little while before using).
- Sugars – use both granulated sugar and brown sugar.
- Baking soda – this helps the cookie bars get a little rise while remaining chewy.
- Salt – sea salt is super necessary for balance in these sweet s’mores cookie bars.
- Vanilla – a little vanilla helps provide depth.
- Graham crackers – we like the classic Honey Maid variety.
- Mini marshmallows – the small marshmallows easily mix in with the dough and get toasty on top of the bars.
- Milk chocolate bars – for the most nostalgic flavor and maximum meltiness, use Hershey’s.
How to Make These S’mores Bars
STEP 1: Prep your oven and baking pan. First, preheat the oven to 350°F. Spray or lightly butter the insides of a square 8×8 inch baking dish and line it with parchment paper, leaving a few inches of parchment overhang to help you remove the bars later.
STEP 2: Make the brown butter. Melt the butter in a pot over medium heat, stirring constantly. Reduce heat to medium-low when the butter starts to bubble, then cook for another 5-10 minutes until it’s browned and smells nutty but not burnt. Place the butter in the fridge until ready to use, or to cool it quickly, place the pot with the melted brown butter in a bowl of ice and whisk it to cool so that it’s soft (not hard) but no longer melted.
STEP 3: Prepare the dry ingredients. Mix the dry ingredients (flour, baking soda, salt) together.
STEP 4: Prepare the wet ingredients. In a large mixing bowl, mix together the softened brown butter and the sugars with a spoon/spatula or electric hand mixer until the texture resembles wet sand. Mix in the eggs, one at a time, then the vanilla. Be careful not to whip too much air into the mixture.
STEP 5: Combine the dry and wet ingredients. Add the dry ingredients to the bowl with the wet ingredients and mix until just combined.
STEP 6: Fold in the s’mores stuff. Using a spoon/spatula, mix in the graham crackers, ½ cup mini marshmallows, and ½ cup chocolate pieces. Be careful not to overmix.
STEP 7: Bake the bars. Press the dough into the prepared baking dish in an even layer, making sure it gets to the edges. Bake for 25-30 minutes, until the cookie base is cooked through.
STEP 8: Make it toasty. Remove cookie bars from the oven and top them with another ½ cup chocolate and 1 cup marshmallows, then place them back in the oven. Broil for 1-2 minutes (rotate pan halfway through), depending on how toasted you want your marshmallows.
STEP 9: Rest the bars. Let cookie bars rest for 30 minutes in the pan, then remove them from the pan and place them on a rack until firm and completely cooled. Once cooled, cut them into 16 squares. Note: cutting them too early may make them fall apart.
Tips for Success
S’mores Cookie Bars with Brown Butter and Toasted Marshmallows
Ingredients
- Butter or cooking spray for greasing pan
- 16 tbsp unsalted butter (227g) 2 sticks sliced into tablespoons (1 cup total)
- 2 ¼ cups all-purpose flour (about 280g) spooned & leveled
- ¾ tsp baking soda
- 1 tsp sea salt
- ¾ cup brown sugar packed
- ¾ cup granulated sugar
- 2 eggs room temperature
- 1 tsp vanilla
- 1 cup graham crackers broken into 1-inch pieces (about 4 sheets)
- ½ cup mini marshmallows for mixing into dough
- 2 1.55 oz Hershey’s chocolate bars chopped (about 1/2 cup)
- 1 cup mini marshmallows for topping bars
- 2 1.55 oz Hershey’s chocolate bars broken into squares/pieces (about 1/2 cup)
Instructions
- Preheat the oven to 350°F.
- Spray or lightly butter the insides of a square 8×8 inch baking dish and line it with parchment paper, leaving a few inches of parchment overhang to help you remove the bars later.Butter or cooking spray
- Melt the butter in a pot over medium heat, stirring constantly. Reduce heat to medium-low when the butter starts to bubble, then cook for another 5-10 minutes until it’s browned and smells nutty but not burnt. Place the pot with the melted in a bowl of ice and whisk it to cool the butter so that it’s soft (not hard) but no longer melted.16 tbsp unsalted butter (227g)
- Mix the dry ingredients (flour, baking soda, salt) together.2 ¼ cups all-purpose flour (about 280g), ¾ tsp baking soda, 1 tsp sea salt
- In a large mixing bowl, mix together the softened brown butter and the sugars with a spoon/spatula or electric hand mixer until the texture resembles wet sand. Mix in the eggs, one at a time, then the vanilla. Be careful not to whip too much air into the mixture.16 tbsp unsalted butter (227g), 2 eggs, ¾ cup brown sugar, ¾ cup granulated sugar, 1 tsp vanilla
- Add the dry ingredients to the bowl with the wet ingredients and mix until just combined.
- Using a spoon/spatula, mix in the graham crackers, ½ cup mini marshmallows, and ½ cup chopped chocolate bars. Be careful not to overmix.1 cup graham crackers, ½ cup mini marshmallows, 2 1.55 oz Hershey’s chocolate bars
- Press the dough into the prepared baking dish in an even layer, making sure it gets to the edges. Bake for 25-30 minutes, until the cookie base is cooked through.
- Remove cookie bars from the oven and top them with ½ cup chocolate squares and 1 cup marshmallows, then place them back in the oven. Broil for 1-2 minutes (rotate pan halfway through), depending on how toasted you want your marshmallows.2 1.55 oz Hershey’s chocolate bars, 1 cup mini marshmallows
- Let cookie bars rest for 30 minutes in the pan, then remove them from the pan and place them on a rack until firm and completely cooled. Once cooled, cut them into 16 squares. Note: cutting them too early may make them fall apart.
