S’mores Cookie Bars are gooey, marshmallow-filled, chocolate-layered, and graham-cracker oatmeal crumb coated perfection.
author’s note
No Campfire? Make These Instead!
There are few desserts that disappear faster at my house than anything S’mores-inspired. The problem? I don’t exactly have bonfires happening every night. And honestly, sometimes I want all those classic flavors without smelling like smoke or trying to keep marshmallows from catching fire.
So I started playing around with turning my favorite summer treat into a bar. I knew I wanted more than just graham crackers and chocolate layered together. I wanted a thick, chewy cookie base with some texture and flavor built right in.
After a few test batches, these S’mores Cookie Bars became my favorite version. The oatmeal cookie layer adds a soft and chewy texture, the marshmallow fluff stays perfectly gooey, and the graham cracker crumble on top gives that unmistakable S’mores flavor. The first time I made them, I cut into the pan while they were still slightly warm and immediately knew I had a problem. They disappeared way too fast.
And honestly? I kind of love that they taste like summer, no matter what month I make them.
S’mores Cookie Bars Ingredients
| Ingredient | Tips & Swaps |
|---|---|
| Butter | Let the butter cool before mixing. Hot butter can make greasy bars. |
| Light brown sugar | Pack the sugar when measuring for the right sweetness and texture. |
| Old-fashioned oats | Avoid quick oats or steel cut oats; they won’t work in this recipe. |
| Milk chocolate chips | I love milk chocolate for classic S’mores flavor. Dark or semi sweet work too. |
| Marshmallow creme | Warm for a few seconds before spreading. It makes life much easier. |
| Graham crackers | Crush coarsely instead of turning them into dust. Bigger bits add texture. |
How To Make S’mores Cookie Bars Tips
- Make dough: Mix together the butter, sugar, flour, oats, baking soda, and salt.
- Bake the base: Press half the dough into a lined baking pan and bake briefly.
- Filling: Sprinkle chocolate over the crust, then spread marshmallow fluff on top.
- Finish topping: Stir crushed graham crackers into remaining dough and crumble over the marshmallow layer.
- Bake & cool: Bake until lightly golden, then let cool completely before slicing into bars.
chelsea’s recipe tip
My Top Tips For Success
- Use an 8×8 pan: I prefer it for thick bakery-style bars.
- Use high-quality chocolate: Better chocolate melts smoother and tastes richer.
- Let marshmallow peek through: Don’t stress about completely covering the top layer.
- Cool fully before cutting: Warm bars are delicious, but fully cooled bars slice much cleaner.
Storage
- 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 Dessert Recipes:
S’mores Cookie Bars
Video
Equipment
- 8 x 8-inch baking pan or 9 x 9-inch for thinner bars
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 creme 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).
Recipe Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
LOVE the new look! it is gorgeous, and the bars look equally as good!
Congrats on the new site design – love it!
LOVING all the s’mores recipes and the new & improved site!!! truly looks fabulous – All the best with it!!! xx
Oh my goodness, these look amazing.
I have really enjoyed all these s’mores week posts. Wish I could taste every single one of them! And I absolutely love your new blog design, Chelsea. 🙂 These bars look so good with that gooey marshmallow. Mmmm. 🙂 Pinned!
Girlfriend, I dub you Queen of creative desserts! Your creativity amazes me! I wish I had that knack for desserts! And LOVE the new site! It looks awesome!!
Love the new design and these S’mores gooey bars!! Such a fabulous combination, need to make these!
I love the site it looks INCREDIBLE!!! and the recipe looks AMAZING!!!
Chelsea, that moving picture is AWESOME!! and so are these bars, obviously. Ok, you totally sold me by saying that these are your absolute favorite s’mores dessert ever!! So creative to use oatmeal. I was always one to reach for any dessert with oatmeal in it!! Pinned for sure, thanks lovely!
Love the new site layout and these AMAZING s’mores bars!