Made with a foolproof oatmeal cookie dough (that requires no mixer!), marshmallows and chopped chocolate, these oatmeal cookie s’mores bars are both extremely easy to make and delicious to eat.
My family are obsessed with them, I actually have to hide these from my husband to make sure my kids and I get a square! If your kids keep asking for s’mores and you just don’t feel like making a fire just to toast a stack of crackers, marshmallows and chocolate… Make these instead!
I will never forget the first time I ate a marshmallow. It was stark pink and yellow and it had a comic mouse on the package, and for some reason nobody told me I was supposed to roast it over the fire.
It’s not like I cared, I was completely mesmerized by the entire pillowy-yet-sticky, soft-yet-chewy consistency. And the mounds of sugar and artificial flavor nobody cared about.
Yes, those were the glorious 90ies.
I eventually learned to toast them. And I made sure my kids knew what toasted marshmallow tastes like as soon as they were able to handle an open fire situation and a sticky mess.
And I will even add leftover sweet potato casserole with marshmallows to my oatmeal because I just love those little white pillows so much.
It may come as a shock to you then…
That to this day I have never eaten a real s’more. You know, the one you make over a campfire with graham crackers, chocolate and a marshmallow.
a) I’m not often around campfires these days and b) I’m not in a season of life where I feel like assembling stacks of something to then hold them over the fire without covering my entire life in melted chocolate and gooey marshmallow.
I mean, I’ll get there. Some day. When I don’t have tiny humans run my days.
Either way, these oatmeal cookie s’mores bar are my version of the glorious summer treat for now.
The amount of sugar and butter are, what I call, mindful. Not missing or in such a small dose that you might as well be eating cardboard (this is still dessert, after all). But also not a case of seven sticks of butter and five cups of sugar. You get what I mean.
You don’t need a mixer to make the cookie dough (a whisk and your arm will do just fine), you can assemble the whole thing in no time and you’re rewarded with a bunch of satisfying gooey-gooey dessert bars.
Bottom line: These Oatmeal Cookie S’mores Bars are extremely, extremely easy to make.
And it’s actually fun to assemble with little kids (I don’t imagine having little kids help make real s’mores would be a lot of fun – all I can think about are the sticky chocolate fingerprints on my white walls, and I’m not even a person who’s overly concerned about getting walls dirty.)
How To Make Oatmeal Cookie S’Mores Bars:
First, you’re going to want to line a 20×20 inch pan with parchment paper (leave an overhang or you’ll never get the bars out of the dish) and preheat your oven.
Then, mix the dry ingredients for the cookies. I use whole wheat flour to underline the nutty taste of the oatmeal, but you do you, sugar. Read: It works with either whole wheat or white flour and you can use whatever you want.
For the wet ingredients, first you’ll need to cream the softened butter. Just whisk it until it looks all funky. Then whisk in the brown sugar for a minute or two (give it your best), and finally the egg and then the vanilla.
In the end, you should have a smooth, pale-ish and creamy mass in your bowl. (The photo below is from my tutorial on making oatmeal cookies, so the ingredients are all together in a bowl already. I just wanted you to see what the egg mix should look like.)
Add the dry ingredients and fold them in with a rubber spatula until no oat flake is left dry. 2/3 of this you’ll press very tightly into the prepped baking pan.
I like using clean, damp hands to press the cookie dough into the pan, it’s just faster and easier than trying to handle the sticky dough with a spatula.
Then, sprinkle most of the chopped chocolate over the base, and then the marshmallows. If you’re using minis they can go on whole. I only had regular so I snipped them in half with my kitchen shears to be able to distribute them more evenly.
Finally, use a small cookie scoop to scoop balls of cookie dough. Flatten them and place them on top of the marshmallow layer. You don’t need to cover it entirely (I love it when the marshmallows bubble up, and it also looks way prettier and gooey-er). But make sure the remaining dough is evenly distributed over the marshmallows.
Then, sprinkle with the remaining chocolate (doh, I totally forgot this in the video, I had to take the pan out of the oven to sprinkle on the chocolate 🤦🏻♀️) and bake.
Once they’re out of the oven, they’ll be all gooey and won’t feel set. That’s totally normal. Please don’t overtake them, or they’ll be terrible and the marshmallows on top will burn!
Cool them in the pan for at least 30 minutes before lifting them out to slice!
P.S: I sliced them into 9 squares to take pretty photos, but they are quite rich so I actually slice them into 12-16 bars if I’m just making them for us and not to share here on the blog.
I mean, look at them. I’m pretty sure they make up for not having actual s’mores 😉
See how to make oatmeal cookie s’mores bars:
This video will show you how to make the bars of your dreams. And I also have a bunch of cute heads interrupting in the background 🙈
(FYI, if you’re looking at this post on your desktop computer or laptop, the video could also be playing in the sidebar!)
Grab the printable recipe for these oatmeal cookie s’mores bars:
For the cookie dough:
- 1.25 cups whole wheat flour
- 1 cup rolled oats
- 3/4 teaspoon baking soda
- 1/2 teaspoon salt
- 8 tablespoons butter, softened
- 1/2 cup light brown sugar
- 1 large egg
- 2 teaspoons vanilla extract
To Make the Bars:
- 6 ounces chopped dark chocolate
- 6 ounces mini marshmallows
- Preheat the oven to 340°F and line a 20x20 inch baking pan with parchment, leaving an overhand on all sides.
Make the cookie dough:
- Add the flour, oats, soda and salt to a small bowl and mix well. Set aside.
- In a separate bowl, whisk the softened butter until creamy. Add the sugar and whisk for a minute or two. Add the egg and keep whisking until it's well incorporated. Finally, add the vanilla and mix it in until smooth.
- Add the dry ingredients to the wet and fold with a rubber spatula until well combined, and no more dry oats are left.
Assemble the bars:
- Press 2/3 of the cookie dough into the bottom of the prepared baking pan.
- Evenly sprinkle most of the chopped chocolate over the base, then add the marshmallows on top. Press down lightly.
- Scoop the remaining cookie dough with a small cookie scoop. Flatten with your hands and evenly add on top of the marshmallow layer. You don't need to cover the entire top, but make sure your blobs of dough are evenly distributed.
Bake the bars:
- Bake the bars for around 25 minutes, or until the oatmeal cookie dough is set and the top is golden brown. They will still be gooey and very soft, that's fine!
- Cool the bars in the pan for at least 30 minutes before lifting them out to slice.