These soft, chewy and gooey high altitude s’mores chocolate chip cookie bars have layers of Biscoff cookie butter cookie dough, marshmallow fluff, crumbled graham crackers and chocolate chips. These layered s’mores bars are chewy, chocolatey, easy to make, and so incredibly delicious! This is a perfect dessert to take to a summer get together, and they disappear fast. A sweet and sticky treat like this will have everyone saying, gimme s’more!
Looking for more recipes like this one? You’ll love my s’mores cake with homemade marshmallow fluff, s’mores no churn ice cream, and chocolate chip cookie brownies.
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Why You’ll Love These Bars
Easy to Make. You don’t even need a mixer to make these, since the cookie dough is made with melted butter, and comes together easily with just a bowl and spoon. And while you can make homemade marshmallow fluff if you like, I used jarred fluff in today’s s’mores cookie bars, just to save myself a little more time.
All the Best Textures. There’s the layer of chewy cookie bars on the bottom and the sweet and gooey marshmallow fluff. The cookie layer on top gets a bit crisp, and the crunchy graham crackers and chunks of chocolate add the perfect contrast in texture.
Perfect for Summer Parties. Since this is such an easy recipe to make, you can make it in the morning, and the bars will be cooled and ready by the afternoon. Or make it the night before, and keep them refrigerated until ready to serve. And if an 8-inch pan doesn’t make enough, you can easily double the recipe and bake it in a 9×13 pan for a bigger crowd. I made these for a 4th of July get together, and they were such a hit!
See the recipe card at the end of the post for the full ingredients list and instructions.
Ingredients
- Butter. Unsalted butter keeps these bars moist and adds a rich buttery flavor.
- Cookie Butter. The Biscoff cookie butter adds more graham cracker flavor, and keeps the bars soft, moist and chewy.
- Sugar. White granulated sugar + light brown sugar adds sweetness and moisture, with a hint of molasses to complement the graham cracker flavor.
- Egg + Egg Yolk. Adds structure and binds the cookie dough together.
- Vanilla Extract. Flavor.
- All-Purpose Flour. Gives the cookie dough structure and strength.
- Corn Starch. Lowers the percentage of protein in the flour and gives the bars a soft, chewy texture.
- Salt. Balances the sweetness.
- Chocolate Chips. I used dark chocolate, but you can use semi-sweet or milk if that’s what you like.
- Graham Crackers. Adds crunch and flavor.
- Marshmallow Fluff. Whether you call it marshmallow fluff or marshmallow creme, it adds a sticky, creamy, gooey marshmallow filling in these s’mores bars.
- Flaky Salt. A touch of flaky salt on top adds more flavor and balances the sweetness.
Instructions
Make the cookie dough.
- Preheat the oven to 350 F, and line an 8-inch baking dish with parchment paper.
- In a small saucepan, melt the butter over medium heat. Add the cookie butter and stir until melted. Remove from the heat.
- In a bowl, mix together the melted butter, cookie butter, sugar and brown sugar. The mixture will be grainy.
- Add the egg, egg yolk and vanilla, and mix until the mixture smooths out with a “ribbony” consistency (it should easily flow off the spoon like ribbons).
- Separately, whisk together the flour, corn starch and salt. Stir the dry ingredients into the cookie butter mixture until moistened. Set aside to cool for 10 minutes, then stir in the chocolate chips (reserve a few tablespoons of chocolate chips to sprinkle on top).
TIP: Instead of sprinkling chocolate chips on top, break up a Hershey’s milk chocolate bar, and scatter the pieces on top of the bars before baking.
Layer the ingredients.
- Use your hands or a spatula to spread or pat 2/3 of the dough into the prepared pan.
- Dollop the marshmallow fluff on top of the dough, then use a small offset spatula to spread it out into an even layer.
- Sprinkle the marshmallow fluff with the crumbled graham crackers.
- Dollop the remaining cookie dough on top of the fluff, leaving gaps for the fluff to peek through. Sprinkle with a few more chocolate chips.
Bake and cool.
- Bake the s’mores bars on the center oven rack for 25 minutes. They should be golden brown on top, with the fluff starting to puff up.
- Cool the bars completely before cutting into squares. To speed up the cooling process, let them cool for 1 hour at room temperature, then refrigerate for 1 – 1 1/2 hours. Sprinkle with flaky finishing salt.
Be sure to read all of my BAKING FAQs where I discuss ingredients, substitutions and common baking questions, so that you can be successful in your own baking!
Frequently Asked Questions
What can I use instead of graham crackers?
If you’re not able to find graham crackers, you can use digestive biscuits or biscoff cookies.
What is cookie butter?
Cookie butter, or Biscoff, is a sweet spread made from ground up spice cookies called speculoos cookies. In Europe, Biscoff is a common alternative to nut butters. The flavor is perfectly reminiscent of the graham crackers in s’mores.
Is there a substitute for cookie butter?
If you’re not able to get cookie butter, you can use creamy peanut butter or almond butter instead. Of course, then your s’mores cookie bars will taste nuttier, and less like a s’more.
Can this recipe be doubled?
Yes, for a double batch, bake the bars in a 9×13 pan. The bake time will be the same.
How long do these bars stay soft?
The leftover bars will stay soft and chewy in an airtight container for up to 3 days. Since marshmallow fluff can get a little weepy when it’s warm, it’s best to keep the bars refrigerated, then let them warm up to room temperature before serving.
You Might Also Like
S’mores Ice Cream 
S’mores Cake Chocolate Chip Cookie Brownies 
Nutty White Chocolate Chip Butterscotch Cookies
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Did you love today’s recipe? Please rate the recipe and let me know in the comments what you thought! Also, be sure to follow Curly Girl Kitchen on Instagram, and tag me when you try one of my recipes so I can see all your delicious creations!
High Altitude S’mores Chocolate Chip Cookie Bars
All recipes on Curly Girl Kitchen are developed for high altitude at 5,280 feet.
Equipment
- 8 inch baking pan
Ingredients
- 6 tbsp unsalted butter
- ¼ cup cookie butter, (Biscoff)
- ¼ cup granulated sugar
- ½ cup light brown sugar, lightly packed
- 1 large egg
- 1 egg yolk
- 2 tsp vanilla extract
- 1 cup all-purpose flour, spooned and leveled
- 2 tbsp corn starch
- ½ tsp coarse Kosher salt (if using table salt, use half the amount)
- ⅔ cup chocolate chips
- 2 graham crackers, crumbled
- 7 oz marshmallow fluff/creme
- ¼ tsp flaky finishing salt
Instructions
- Preheat the oven to 350 F, and line an 8-inch baking dish with parchment paper.
- In a small saucepan, melt the butter over medium heat. Add the cookie butter and stir until melted. Remove from the heat.
- In a bowl, mix together the melted butter, cookie butter, sugar and brown sugar. The mixture will be grainy.
- Add the egg, egg yolk and vanilla, and mix until the mixture smooths out with a "ribbony" consistency (it should easily flow off the spoon like ribbons).
- Separately, whisk together the flour, corn starch and salt. Stir the dry ingredients into the cookie butter mixture until moistened. Set aside to cool for 10 minutes, then stir in the chocolate chips (reserve a few tablespoons of chocolate chips to sprinkle on top).
- Use your hands or a spatula to spread or pat 2/3 of the dough into the prepared pan.
- Dollop the marshmallow fluff on top of the dough, then use a small offset spatula to spread it out into an even layer.
- Sprinkle the marshmallow fluff with the crumbled graham crackers.
- Dollop the remaining cookie dough on top of the fluff, leaving gaps for the fluff to peek through. Sprinkle with a few more chocolate chips.
- Bake the s'mores bars on the center oven rack for 25 minutes. They should be golden brown on top, with the fluff starting to puff up.
- Cool the bars completely before cutting into squares. To speed up the cooling process, let them cool for 1 hour at room temperature, then refrigerate for 1 – 1 1/2 hours. Sprinkle with flaky finishing salt.
THESE ARE SO GOOD. I followed the recipe exactly and it turned out amazing. They also look really cool, lots of texture and dimension. Definitely going to make them again!
I’m so glad you loved them! 🙂