Chocolate S'more Cookie Bars

stack of s'more brownie cookie bar recipe

These thick, fudgy, gooey s’more bars can be made in under an hour… without the campfire! With a graham cracker base, fudgy chocolate cookie dough, and golden marshmallows, these are sure to be your new favorite s’mores dessert!

Makes 12-24 squares

Course Dessert

Cuisine Cookies

Keyword smore brownies, smore cookie bars

Prep Time 20

Cook Time 20

Total Time 1

Servings -24 squares

Calories 540kcal

Author Melissa Rose

Ingredients

¾ cup unsalted butter (i.e. 1 ½ sticks) softened
¾ cup light brown sugar
¾ cup granulated sugar
2 large eggs
2 teaspoons vanilla extract
3 tablespoons light corn syrup Fun fact: this is not the same thing as high fructose corn syrup!
1 teaspoon baking powder not baking soda!
½ teaspoon salt
¾ cup dark cocoa powder I use & recommend Hershey's Special Dark for an affordable option
2 ¼ cup all-purpose flour
16 graham cracker squares (you will need 2 sleeves)
10-ounce bag mini marshmallows

Optional Toppings:

1-2 Hershey bars (I recommend using two!)
Extra graham cracker pieces

Instructions

Preheat oven to 350°F.
Two notes before starting!
(1) Note that this is a thicker dough that is easiest to make with a stand mixer. If you only have a handheld mixer, you may just need to use a spatula to help mix the flour in.
(2) I created an interactive slideshow of me talking through all my tips & tricks to make these – I recommend tapping through this before you make them!
In a large bowl, use an electric mixer on medium-high speed to cream softened ¾ cup unsalted butter (i.e. 1 ½ sticks), ¾ cup light brown sugar, and ¾ cup granulated sugar for 2 minutes until light and fluffy.
Add the 2 large eggs, 2 teaspoons vanilla extract, and 3 tablespoons light corn syrup and mix on low speed until combined. Scrape down the sides of the bowl so everything can combine.
Add in 1 teaspoon baking powder and ½ teaspoon salt and mix for another 5-10 seconds until combined.
Lastly, add ¾ cup dark cocoa powder and 2 ¼ cup all-purpose flour and mix on medium until combined.
Spray a light-colored metal 9×13 pan with cooking spray, then line pan with two pieces of parchment paper, leaving a 2-inch overhang on each long side so that you will be able to lift the bars out of the pan.
Line the bottom of the pan with graham crackers.
Drop the dough into small chunks in the pan. This will help disperse everything so that you can easily smooth it out. I highly recommend this method rather than trying to spread out a large chunk. Once all dough has been added, use a spatula or your hands to press down the dough into a smooth layer (being sure to get all the corners). Be careful not to shift around the graham crackers too much.
Tip: This dough is a little sticky, so to help spread, I recommend spraying your hands with cookie spray or use place another piece of parchment paper on top and continue pressing down.
Bake bars at 350°F for 18-22 minutes, or until the center no longer looks wet. The center may look a tiny bit underdone but the bars will continue to bake in the hot pan when cooling.
Immediately proceed to next step.
Right after your bars come out of the oven, top with the full 10-ounce bag of marshmallows. Turn on the “BROIL” function on your oven and place the pan on the bottom or middle rack.
Stand by the oven and watch it very closely – do not walk away! When you start to notice a light brown, rotate the pan to avoid any hot spots. Remove from the oven when the marshmallows are golden brown.
If desired, press Hershey bar and graham cracker pieces into the top.
Before cutting, allow the pan to fully cool, then refrigerate for 30-60 minutes to help firm up the chocolate and marshmallows. This will give you the most clean cuts.
Want to get super clean cuts? For this month's baking challenge, I've created a cool interactive slideshow with video tips on how to make these! Be sure to watch this for tips to cut the bars really cleanly!
Store in an airtight container or cover the pan with plastic wrap. If your kitchen is warm or you plan to serve these outdoors, keep referigerated until time to serve to help slow down the marshmallows and chocolate from getting too warm.

Notes

Cocoa Powder: I use and recommend Hershey’s Special Dark Cocoa powder to give them a moist, rich flavor. You can substitute for regular unsweetened cocoa powder, just note that your cookies will have a puffier texture and won’t have the iconic brownie taste.
Storage: Store in an airtight container or cover the pan with plastic wrap. If your kitchen is warm or you plan to serve these outdoors, keep refrigerated until time to serve to help slow down the marshmallows and chocolate from getting too warm.
Freezing: You can freeze them but the graham crackers may get soft & the marshmallows can get sticky after freezing. If you need to make ahead, I would recommend waiting to add/broil the marshmallows until after you thaw the bars.

Nutrition information is based on 24 squares and is calculated using an ingredient database. All numbers should be considered an estimate.

Nutrition