S’mores Cookie Bars
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Thick, chewy, and extra gooey – these s’mores cookie bars have everything you love about the classic campfire treat. We’re using a cookie dough that’s made with graham crackers for that classic s’mores flavor, then the dough is stuffed with a thick layer of milk chocolate and marshmallow fluff.
These s’mores cookie bars will be your new favorite summer treat (although – I urge to make these all year round). The recipe starts with an easy cookie dough recipe – very similar to your favorite blondies or chocolate chip cookie dough – where some of the flour is replaced with crushed graham crackers for the quintessential s’mores flavor. In the middle, there’s entire layer of Hershey’s milk chocolate bars (or whatever milk chocolate is your favorite) and a thick layer of marshmallow fluff. Then more cookie dough goes on top.
These bars are super thick, with a generous layer of chocolate and oozing with gooey marshmallow.
Tip: If you slice the bars while they’re still warm, you’ll have a deliciously ooey, gooey messy treat that’s best if eaten with a spoon. If you wait til they’re fully cooled, you’ll still have a ooey, gooey marshmallow – but you’ll get cleaner cuts, like the bars are pictured.
Making S’mores Cookie Bars
You’ll start with the graham cookie dough.
- Whisk together melted butter, brown sugar and granulated sugar. Keep whisking until you no longer see the butter sitting on top of the sugars.
- Then whisk in the egg, additional egg yolk and vanilla extract. The extra egg yolk keeps them chewier.
- Mix in the flour and salt. Salt is key to balance the sweetness. I always do this by hand without any issues.
- Fold in the crushed grahams.
Then it’s time to assemble the bars.
- Scoop out about 1 cup of cookie dough – this will be for the top half.
- Press the remaining dough into the bottom of the lined pan so that there’s an even layer.
- Place an even layer of milk chocolate on top of the bottom cookie layer.
- I purchased 4 regular Hershey’s milk chocolate bars. I used 3 full bars, and then broke the 4th bar into pieces to cover the top of the bottom cookie layer.
- Spread about 1 1/2 cups of marshmallow fluff (AKA marshmallow creme) on top of the chocolate.
- It’s important that the chocolate goes underneath the fluff – otherwise the bars are very difficult to slice.
- Scoop the remaining cookie dough into balls and flatten. Place on top of the marshmallow layer, covering as much marshmallow as possible.
- It’s fine to have some of the marshmallow layer showing.
The bars will bake for about 30-35 minutes. When they’re finished, the top should look golden brown. If some of the marshmallow layer is exposed (ie not covered by the top layer of cookie dough) then the marshmallow fluff will puff up slightly as the bars bake, creating pockets & pools of gooey marshmallow. If all of the marshmallow is covered, then you’ll end up with a more even layer of marshmallow in the middle.
Ingredient Substitutions
Graham Crumbs: For any UK or Australian bakers (or anyone who can’t access graham crackers/crumbs), feel free to use crushed digestive biscuits instead.
Chocolate: Feel free use your favorite variety of chocolate. I used milk chocolate bars. Dark chocolate or semi-sweet chocolate works too. You could use chocolate chips, but I prefer using entire chocolate bars to mimic a gooey s’more.
Marshmallow Fluff: Do not substitute marshmallow fluff with marshmallows. Marshmallows will melt and dissolve into the graham cookie dough, leaving a sticky, almost hard bottom layer and no gooey marshmallow in the middle.
Mores S’mores Treats to Love:
- Easy S’mores Bars – these have a graham cracker crust
- Golden Graham S’mores Bars
S’mores Cookie Bars
Equipment
- 8×8 inch (20×20 cm) pan
Ingredients
- ¾ cup unsalted butter, melted and cooled slightly
- ½ cup brown sugar, I used light, dark works too
- ¼ cup granulated sugar
- 1 large egg
- 1 large egg yolk, in addition to the whole egg
- 2 teaspoons vanilla extract
- 1½ cup all-purpose flour
- ¼ teaspoon salt
- ½ cup graham crumbs, about 5 sheets of graham crackers
- 2 4 ounce Hershey's Milk Chocolate Bars , or 4 100 gram bars (for those in Canada), or about 1½ cups chocolate chips
- 1½ cups marshmallow fluff, about ½ of a 16 ounce container
Instructions
- Preheat the oven to 350℉ (180℃). Line an 8×8 inch (20×20 cm) square pan with parchment paper so that there's an overhang around the sides.
Make the Cookie Dough
- In a large bowl, whisk together the melted butter, brown sugar and granulated sugar until the melted butter no longer sits on top of the sugar.
- Whisk in the egg, additional egg yolk and vanilla extract until combine.
- Whisk/stir in the flour and salt until no lumps remain.
- Stir in the graham crumbs until evenly distributed throughout the dough.
Assemble the Bars
- Scoop out 1 cup of dough (this is for the top half).
- Press the remaining dough into the bottom of the prepared pan (reserving the 1 cup for the top).
- Place a layer chocolate on top of the dough (or sprinkle with chocolate chips to create an even layer). Depending on the size of your chocolate bars, you will need to break them a bit to create an even layer.
- Spoon the marshmallow fluff on top of the chocolate and spread into an even layer.
- With the reserved cookie dough, scoop into balls/dollops (about 1-2 tablespoons each) and then flatten into disc shapes. Place the flattened dollops on top of the marshmallow layers. Try to cover as much of the marshmallow layer as possible – but leaving some marshmallow to show through.
Bake & Slice
- Bake in the middle of the preheated oven for about 30-35 minutes or until the top is golden and the marshmallow is starting to puff up where exposed.
- Cool the bars in the pan – I let mine cool for about 4 hours, and they were still nice and gooey. For the cleanest cuts, cool for at least 8 hours.
- When ready to bake, lift the bars out of the pan using the overhang of the parchment paper. Place on a cutting board and slice with a sharp knife.
