It’s National S’mores Day, and I’ve been thinking about what makes this treat so special to deserve its own day of honor. The first written recipe for “s’mores” appeared in a Girl Scout handbook in 1927, when Calvin Coolidge was President of the United States— 16 presidents and almost 100 years ago. Amid a sea of other snack trends and fads that have come and gone (I’m lookin’ at you, Hostess pudding pies!), the s’more has stood the test of time. And no wonder! A melty morsel of milk chocolate and campfire-toasted gooey marshmallow, bookended by a sweet and simple whole grain cookie, what’s not to love? 

Like most of you, I’ve enjoyed s’mores since I was a kid in rural upstate New York. But our weather in the South is hot as hell in August, not particularly conducive to a campfire, and I’m sorry to say that the oven and microwave versions of s’mores just don’t cut it. There are appliances out there now for making s’mores indoors, like this one sold through Williams-Sonoma, but who has room for another gadget that only serves one purpose? 

Luckily, I’ve found many other ways to capture the essence of s’mores (along with all the happy feelings they invoke), twisting the ingredients of this summer classic into ice cream, brownies, cocktails and even dessert pizza! When I made s’mores cupcakes last year, I mused that perhaps I could have used up the leftover homemade marshmallow topping by making rice krispie treats, and I considered a s’mores version of those this year, except for one problem— my husband doesn’t like the krispie treats, and I would have been left to eat the entire batch! These s’mores cookie bars are my compromise, and I have no regrets.

They are part s’more, part blondie, part cereal treat and 100% yummy!

What goes into s’mores cookie bars?

The base of my s’mores bars is essentially a blondie dough, with softened butter, brown sugar, egg, vanilla, baking powder and flour. But to emulate the s’mores more distinctly, I used whole wheat pastry flour and also added in honey for additional sweetness and some finely crushed graham crackers, which my hubby was happy to prepare for me. I used two of the little sleeves of Honey Maid “stackers,” which measured out to a little more than one cup of crumbs.

For the ooey-gooey goodness, I went with marshmallow creme, which holds its shape much better than actual marshmallows. When I made my s’mores pizza in 2020, I was disappointed at how much the mini marshmallows deteriorated after they cooled from the oven. Knowing that we would not devour this entire batch of cookie bars right away (though believe me, it was tempting!), I wanted a better, more stable option. Marshmallow creme, made with dried egg whites, is the way to go here, and I used almost an entire jar spread over two-thirds of the blondie dough. It may seem excessive, but isn’t that kind of the point with s’mores? 😏

You could, naturally, whip up a batch of seven-minute frosting in its place if you have the time, but I was getting impatient for my cookie bars. Real Hershey bars were layered over the marshmallow creme (because milk chocolate rules when it comes to s’mores), and then I mixed darker, semi-sweet chocolate chips and crispy Golden Grahams cereal into the remaining blondie dough, lending a cookie-meets-cereal bar vibe to my sticky, delicious treats.

I baked the bars for about 35 minutes, and then let them cool a few hours before removing them from the pan. The result? 

Deliciously sticky, utterly addictive and every bit as ooey-gooey as I wanted them to be, and they have kept on the counter nicely so we can enjoy them for several days. Plus, no campfire required. 😋

Tips for success

As with all baking recipes, it’s best to have all your ingredients lined up, measured and ready to go before you begin. Take your butter out of the fridge an hour ahead so that it isn’t rock solid, and let your egg come to room temperature. Use extra bowls if that’s what it takes to have everything ready for mixing as the recipe indicates. For years, I considered myself to be a mediocre baker, but I’ve come to learn that my failing was mostly in preparation. Get your ducks in a row, and watch your baking game improve!

Following the steps in order does make a difference. If you don’t cream together the butter and sugar before adding in the other ingredients, the texture of your cookie bars may be quite crumbly. When you mix in the flour, do so only long enough to fully incorporate it. Overmixing will lead to gluten development, and you don’t want that. Use the paddle attachment on your mixer, or use a firm spatula to press the ingredients together by hand.

When layering the marshmallow creme, try to keep it about an inch away from the edges of the pan so that it doesn’t stick and burn. Keep in mind that when you press the chocolate bars and cookie dough topping, the creme will smoosh and spread. Give it room to do so.

If possible, use a metal pan to bake these cookie bars. You can see in my photos that I used a ceramic baking dish (it’s all I have in this size), and these simply do not heat as quickly or evenly as a metal pan.

After baking, give these cookie bars plenty of time to cool before you attempt to lift out the parchment sling. The marshmallow and chocolate will be very hot, and thin enough to ooze out everywhere, making a mess and potentially burning your hands. They will still be delicious when cool, and if you wish, you can pop your cookie bar into the microwave for a few seconds to recapture the ooey-gooey stretch of the marshmallow.

S'mores Cookie Bars

• Servings: 9 or 16, depending on how you cut
• Prep Time: 20 minutes
• Cook Time: 35 minutes
• Difficulty: Average
• Print

These are part s'mores, part blondie, part cereal bar and 100% ooey-gooey delicious!

Ingredients

• 1 stick salted butter, softened
• 1/2 stick unsalted butter, softened
• 3/4 cup light brown sugar, packed
• 3 Tbsp. honey
• 1 egg, room temperature
• 2 tsp. real vanilla extract
• 1 cup whole wheat pastry flour (sub regular or white whole wheat, or use all a-p if desired)
• 1/2 cup all-purpose flour
• 1 tsp. baking powder
• 1/2 tsp. salt
• 2 pouches Honey Maid “stackers” graham crackers, crushed fine
• 2/3 cup semi-sweet chocolate chips
• 2/3 cup Golden Grahams cereal
• Most of a 7 oz. jar marshmallow creme
• 3 standard size Hershey milk chocolate bars

Note: For easy removal of cookie bars, layer ingredients over criss-crossed parchment laid inside a 9-inch square baking pan. Overlap the paper so that you can use it as “handles” for lifting the cookie bars out after they’ve cooled.

If possible, use a metal baking pan, as glass or ceramic (as I used) tends to heat more slowly, causing the bottom to be slightly underdone.

Directions

1. Preheat oven to 350° F, with oven rack in the center position. Prepare 9” square baking dish by lining with crossed pieces of parchment paper, overlapping the sides of the dish.
2. In a stand mixer fitted with paddle blade, beat butter on medium high speed until fluffy. Add honey and then brown sugar a little at a time, beating until fluffy again. Add egg and vanilla, beating until evenly blended.
3. Whisk together flours, baking powder and salt in a medium bowl. With mixer running, add flour by the spoonful until all is incorporated. Turn off mixer and scrape dough off beater. Add crushed graham crumbs and use a silicone spatula to press and blend them into the dough. Do not overmix.
4. Transfer about 2/3 of the cookie dough to the parchment lined baking dish. Butter hands and press evenly over parchment. The dough will be very soft and sticky. Add the semi-sweet chips and cereal to the remaining dough, pressing firmly with the spatula to mix them in completely. Set aside for topping.
5. Butter an offset spatula (or dip into hot water) and spread the marshmallow creme evenly over the cookie dough, keeping it about one inch away from the edges.
6. Break the Hershey bars into four sections each and arrange them evenly over the marshmallow layer, gently pressing so that the marshmallow oozes up between the chocolate pieces.
7. Use a scoop, spoon or your fingers to place dollops of the remaining cookie dough over the chocolate pieces, taking care to leave only small gaps for the marshmallow to bubble through.
8. Bake 30 to 35 minutes (depending on your oven), until cookie batter is just barely baked through and the peekaboo marshmallow creme is lightly browned. Remove from oven and cool on a rack for a few hours before lifting out the parchment and cutting into squares.