S’mores Cookie Bars are gooey, marshmallow-filled, chocolate-layered, and graham-cracker oatmeal crumb coated perfection.

Try these Golden Grahams® cereal S’mores bars or S’mores cookies next!

Holding a s'mores cookie bar, displaying its gooey and irresistible inside.

A Must-Make S’mores Treat!

There are few things I love more in the summer than S’mores. And since bonfires and homemade S’mores aren’t as readily available as I’d like, I’ve resorted to making as many treats as possible with plenty of chocolate, lots of marshmallows, and graham crackers.

And S’mores Cookie Bars are one of my favorite creations as of late. These bars begin with a soft, chewy, and sugary oatmeal cookie layer and are loaded with creamy milk chocolate and fluffy sweet marshmallows.

  • Butter: Use unsalted butter to perfectly control the amount of salt in the bars.
  • Light brown sugar: Pack the sugar when measuring.
  • Old fashioned oats: Avoid quick oats or steel cut oats; they won’t work in this recipe.
  • Flour: Stick with all-purpose flour for the best texture.
  • Baking soda: Don’t skip this ingredient—it’s key for the right texture.
  • Salt: It balances and intensifies flavors
  • Milk chocolate chips: Semi sweet or dark chocolate also work.
  • Marshmallow fluff: Jet-Puffed Marshmallow Creme® is by far my fave.
  • Graham crackers: Crush them to a coarse texture to avoid large chunks.
Crafting s'mores cookie bars, from creating the cookie layer to adding chocolate chips, marshmallow fluff, and the crumble topping, displaying the finished bars.
  1. Prep: Use an 8×8 pan for thicker bars.
  2. Make dough: Ensure butter is cooled to avoid greasy bars.
  3. Press half of the dough into the pan: Press evenly for uniform baking.
  4. Bake: Keep an eye on the crust—don’t overbake it.
  5. Chocolate & marshmallows: Warm the fluff to make it easier to spread.
  6. Add graham crackers: Crush crackers coarsely to avoid large chunks.
  7. Add top layer of dough: Don’t worry about covering it completely—let the marshmallow peek through.
  8. Bake: Keep an eye on the top to prevent overbaking.

Recipe Tips

  • Line the baking pan. These bars are sticky! Make sure to line the pan with parchment paper for easy removal.
  • Spoon and level the flour: to avoid packing too much flour into the cookie base. Watch the linked video if you need some guidance.
  • Use high-quality milk chocolate for best results. You’ll get both a better melt and better flavor. My favorite for S’mores Cookie Bars is Ghirardelli® or Guittard®. Cheaper brands can have a waxier content that is far less flavorful.
Fork taking a delightful bite out of a s'more cookie bar, revealing its delectable center.

Storage

Leftovers?

  • Cool and Cut: Allow bars to cool completely in the pan, then lift them out using the parchment paper and cut into squares.
  • Store Airtight: Place bars in an airtight container with parchment paper between layers to prevent sticking.
  • Keep Fresh: Store at room temperature for up to 3 days or refrigerate for up to 1 week.

More Delicious Desserts

5 from 5 votes
These S'mores Cookie Bars have everything you love about campfire s’mores, all packed into a gooey, layered treat! Melty marshmallows, rich chocolate, and a graham cracker oatmeal crumb crust that holds it all together.
Prep Time: 25 minutes
Cook Time: 21 minutes
Total Time: 46 minutes
Servings: 14 bars

Equipment

Ingredients

  • 3/4 cup unsalted butter partially melted and cooled
  • 3/4 cup light brown sugar firmly packed
  • 1 cup all-purpose flour
  • 1 cup old fashioned oats do not use quick or steel oats
  • 1 teaspoon baking soda
  • 1/2 teaspoon salt
  • 1 (12-ounce) bag milk chocolate chips
  • 1 (7-ounce) jar marshmallow fluff I use Jet-Puffed Marshmallow Creme
  • 2 graham crackers

Instructions 

  • Preheat oven to 350°F. Line an 8×8 or 9×9-inch baking pan with parchment paper and set aside. I prefer 8×8 pan for thicker bars, but either works.
  • In a large bowl, mix the melted and cooled butter (see note 1), brown sugar, flour, oats, baking soda, and salt. Stir until combined in a thick cookie dough. Divide the mixture in half and press one half into the prepared pan.
  • Bake at 350℉ for 8 minutes, then remove.
  • Immediately out of the oven, sprinkle the chocolate chips evenly over the cookie crust. Warm the marshmallow fluff in the microwave (make sure there is no metal/foil topping on the fluff or don’t microwave) for 7 seconds. Spoon the marshmallow fluff on top of the chocolate chips and, working slowly and carefully, gently smooth into one layer.
  • Crush the 2 graham crackers (I put them both in a bag, seal the bag, and crush with a wooden spoon or handle of a knife; just a coarse crush is enough). Add the crackers to the rest of the cookie dough mixture and stir to combine. Crumble the cookie dough mixture over the marshmallow fluff. Bake another 13–15 minutes until the top layer is lightly browned.
  • Remove from oven and allow to cool at room temperature for at least 1 hour before cutting into the bars. Using the parchment paper overhang, pull bars out and cut with a sharp knife. Best enjoyed within 2–3 days (store in an airtight container).

Video

Recipe Notes

Note 1: Don’t add hot butter to the sugar—it will melt the sugar and cause greasy bars.
Storage: Store bars in an airtight container with parchment paper between layers to prevent sticking for up to 3 days, or refrigerate for up to 1 week.

Nutrition

Serving: 16bars | Calories: 205kcal | Carbohydrates: 32.9g | Protein: 1.9g | Fat: 9.1g | Cholesterol: 23mg | Sodium: 42mg | Fiber: 1g | Sugar: 17g

Nutrition information is automatically calculated, so should only be used as an approximation.

 

Meet Chelsea


Hello, and welcome to Chelseaโ€™s Messy Apron! Iโ€™m Chelsea, the recipe developer, food photographer, and writer behind the site. Iโ€™m passionate about creating simple, reliable, and delicious recipes that anyone can make.

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5 from 5 votes

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Recipe Rating




43 Comments

  1. Sarah says:

    I made these bars this weekend and they are SOOOOOOOO GOOD!!! I had to add a few minutes in the oven (4 minutes first time in the oven, 6 minutes second time in the oven) because my oven runs cooler than it’s supposed to. But other than that, I followed the recipe exactly and they were perfect. My fiance, who doesn’t like S’mores, begrudgingly took a bite because I forced him, but then proclaimed that the bars were delicious. My father stated that the bars were the best thing he’s tasted in a long time. Thank you so much for the recipe!

    1. chelseamessyapron says:

      Thank you SO much Sarah for taking the time to review these and I so appreciate all your kind words! Glad you fiance liked them – haha my husband was the same ๐Ÿ™‚ He says he doesn’t really like s’mores desserts but loved these!

  2. Rach says:

    Can I double the recipe and put in 9×13 pan?

    1. chelseamessyapron says:

      Hi Rach! I haven’t tried it, but I don’t see why that wouldn’t work. You will just need to watch the baking times and adjust for a larger pan!

  3. Jocelyn says:

    Love love love these s’mores bars!! I wish I had one to stuff my face with right now! ๐Ÿ™‚

  4. Thalia says:

    i am seeing too many delicious smores recipes of late and these bars are no exception! i am SO craving one right now..

  5. dina says:

    these look addicting!

  6. Kayle says:

    5 stars
    These bars are so insanely gooey and s’mores-y (new adjective) and just I want to eat an entire pan by myself. so yeah.

  7. Jaren (Diary of a Recipe Collector) says:

    These look super yummy! I love the new design too!

  8. Jenn@eatcakefordinner says:

    Love the new look!!!

  9. Ashley says:

    Oatmeal cookie and s’mores combined??? Girl these are awesome!!

    And I love the new design – especially all the whisks!! ๐Ÿ™‚

  10. Danae says:

    I’m loving these oatmeal cookie s’mores gooey bars, all the goo has me drooling and wishing I had a pan right now! Pinning.