Prepare for an explosion of flavor with these utterly irresistible Reese’s Peanut Butter S’mores Oatmeal Cookie Bars! We’ve taken all your favorite campfire treat elements and blended them with the creamy, dreamy goodness of Reese’s peanut butter, all nestled in a comforting oatmeal cookie base. Each bite is a journey into total indulgence – gooey, rich, and outrageously awesome!

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Reese’s Peanut Butter S’mores Oatmeal Cookie Bars: A Dream Dessert

Welcome to a week of S’mores celebration! For ages, I’ve been dreaming up the most innovative and delightful S’mores recipes, and it was a delightful challenge to narrow down my favorites. But these extraordinary bars? They were always going to make the cut. Forget the campfire; these Reese’s Peanut Butter S’mores Oatmeal Cookie Bars bring all the magic of that classic treat right into your kitchen, elevated to an unreal level of deliciousness. Get ready to experience S’mores like never before!

My inspiration for this decadent creation started with my beloved Reese’s Peanut Butter Oatmeal Cookie Bars. I envisioned a pure S’mores experience, but let’s be honest, it’s incredibly hard for me to resist including Reese’s! And we all know that peanut butter is undeniably S’mores’ best friend, adding a layer of creamy, salty-sweet complexity that perfectly complements the traditional flavors. This fusion results in a dessert that’s truly more than the sum of its parts.

The Ultimate S’mores Bars: Unpacking the Layers of Flavor

What truly sets these bars apart are a few clever tweaks that transform them from a simple cookie bar into a gourmet S’mores sensation. One pivotal change was incorporating graham cracker crumbs directly into the cookie dough. Initially, I had a slight hesitation, but that skepticism vanished with the very first bite. The graham cracker crumbs infuse the bars with that distinct, honeyed flavor and a subtle textural crunch that mimics the experience of a perfectly toasted graham cracker. This ingenious addition truly makes these cookie bars the ultimate S’mores treat, delivering authentic flavor without the need for individual crackers.

For peanut butter enthusiasts, this recipe is an absolute dream. The cookie dough itself is rich with creamy peanut butter, further enhanced by the inclusion of delightful Reese’s peanut butter chips. This double dose of peanut butter ensures every morsel is packed with that beloved nutty flavor. And let’s not forget the humble oats! I’m a steadfast fan of oatmeal in baked goods; it not only adds a lovely chewiness and depth of flavor but also provides a sturdy structure that holds these magnificent bars together. Plus, if I include oatmeal, I can almost convince myself these glorious treats are healthy – right?

Reese's Peanut Butter S'mores Oatmeal Cookie Bars with rich peanut butter cookie dough

Once two-thirds of the rich, peanut-butter-infused cookie dough is pressed into the baking dish, the real magic begins with the chocolate layer. We’re talking about a generous spread of pure chocolate bliss. Seven full-size Hershey’s chocolate bars are carefully placed over the cookie dough. At this point, the aroma alone is enough to make you swoon, but true S’mores demand more! It’s time for the ethereal cloud of marshmallows.

Reese's Peanut Butter S'mores Oatmeal Cookie Bars with marshmallow fluff layer

For the marshmallow component, fluff is absolutely the superior choice. Its smooth, spreadable consistency makes it incredibly easy to evenly coat the Hershey’s chocolate bars, creating a continuous, gooey layer. As these bars bake, the marshmallow fluff undergoes a magical transformation: it begins to peek through the cracks in the top cookie layer, becoming wonderfully golden and perfectly toasted, just like marshmallows roasted over an open flame. This delightful charring adds a depth of flavor and texture that is quintessential to the S’mores experience.

To ensure every bite delivers maximum Reese’s goodness, I finely chopped a generous amount of Reese’s miniatures and carefully folded them into the remaining cookie dough. This final, peanut butter-packed dough is then artfully dropped by the teaspoonful over the marshmallow layer. It’s perfectly okay if it doesn’t completely cover the fluff; those toasted marshmallow peeks are part of the charm! Resisting the urge to grab a spoon and dive in at this stage takes incredible willpower, but trust me, the wait is more than worth it.

Reese's Peanut Butter S'mores Oatmeal Cookie Bars with top cookie layer

A relatively short trip to a preheated oven is all it takes for these culinary masterpieces to emerge. The result is a sight to behold: the most beautiful, golden-brown cookie bars you could ever imagine. The top layer achieves a perfect texture, while beneath, the marshmallow fluff toasts and the chocolate melts into a rich, decadent pool.

Baked Reese's Peanut Butter S'mores Oatmeal Cookie Bars, golden brown and gooey

Aren’t they absolutely glorious? While my schedule unfortunately didn’t allow for immediate photos of the chocolate in its ultimate ooey-gooey, molten state, the perfection of that marshmallow layer is undeniable. It’s beautifully browned and caramelized, hinting at the incredible texture and flavor within. Each layer of these bars offers pure, unadulterated indulgence. The thick Hershey’s chocolate bar layer is particularly noteworthy – so rich and intensely chocolatey, it commands attention with every bite. The robust, peanut-butter-oatmeal cookie layers perfectly sandwich all these delightful S’mores flavors, making them a sensational treat in their own right, even before considering the incredible filling. They are not just bars; they are an experience.

Tips for Perfect Peanut Butter S’mores Oatmeal Cookie Bars

**Room Temperature Eggs:** Ensure your eggs are at room temperature for better emulsion with the butter and sugar, resulting in a smoother, more uniform dough.
**Don’t Skip the Chill Time:** Refrigerating the dough for at least 30 minutes is crucial. This helps solidify the butter, making the dough easier to handle and preventing the bars from spreading too much during baking.
**Parchment Paper is Your Friend:** Lining your baking dish with parchment paper (leaving an overhang on the sides) makes for effortlessly lifting the entire slab of bars out once cooled, simplifying the cutting process.
**Cool Completely:** Patience is key! Allow the bars to cool completely before attempting to cut them. This ensures clean, defined squares and prevents a gooey, crumbly mess.
**Evenly Spread Marshmallow Fluff:** For that beautiful toasted marshmallow effect, try to spread the fluff as evenly as possible over the chocolate layer.
**Customization is Key:** Feel free to experiment with different types of chocolate bars or even add a sprinkle of sea salt on top for an extra flavor boost.

Why These Bars Will Be Your New Favorite Dessert

Beyond the irresistible combination of flavors, these Reese’s Peanut Butter S’mores Oatmeal Cookie Bars offer convenience and versatility. You get the beloved taste of S’mores without the need for a fire pit, making them a perfect year-round treat for parties, potlucks, or simply a cozy night in. The hearty oatmeal base makes them surprisingly satisfying, while the rich peanut butter and molten chocolate ensure they remain a truly decadent dessert. They’re also wonderfully portable, making them an excellent choice for lunchboxes or on-the-go snacks (if they last that long!).

Variations to Try

**Nut Butter Swap:** While Reese’s and peanut butter are divine, feel free to try almond butter or cashew butter for a different nutty twist.
**Chocolate Choices:** Instead of Hershey’s bars, use milk chocolate, dark chocolate, or even white chocolate for varied flavor profiles. Chocolate chunks or chips can also work!
**Add-ins:** Consider sprinkling mini chocolate chips, chopped nuts, or even a dash of cinnamon into the cookie dough for extra layers of flavor.
**Toppings:** A drizzle of melted chocolate or peanut butter after cooling can take these bars to another level of visual appeal and taste.

Storage Instructions

To keep your Reese’s Peanut Butter S’mores Oatmeal Cookie Bars fresh, store them in an airtight container at room temperature for up to 3-4 days. For longer storage, you can refrigerate them for up to a week. If you plan to freeze them, wrap individual bars tightly in plastic wrap and then place them in a freezer-safe bag or container for up to 2-3 months. Thaw at room temperature before serving.

Ready to bake a batch of pure happiness? These Reese’s Peanut Butter S’mores Oatmeal Cookie Bars are guaranteed to be a crowd-pleaser and a new family favorite. Don’t just take my word for it – whip up a batch today and experience the magic for yourself!

More S’mores Favorites to Indulge In

S’mores Pudding Parfaits
No Bake S’mores Cheesecake Bars
S’mores Rice Krispies Treats Pinwheels
S’mores Cinnamon Rolls with Marshmallow Frosting
5 Minute Mocha S’mores Dip

How To Make Peanut Butter S’mores Oatmeal Cookie Bars

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Peanut Butter Smores Oatmeal Cookie Bars

These Reese’s Peanut Butter S’mores Oatmeal Cookie Bars are a total indulgence in every single bite, combining all your favorite flavors into one unforgettable dessert!

Course
Dessert

Cuisine
American

Keyword
peanut butter s’mores oatmeal cookie bars

Prep Time

15 minutes

Cook Time

25 minutes

Chill Time

30 minutes

Servings

24
bars

Calories

328
kcal

Author
Trish – Mom On Timeout

Ingredients

12 tablespoons butter melted
2 cups light brown sugar
½ cup creamy peanut butter
2 eggs room temperature
1 tablespoon vanilla extract
1 ½ cups all-purpose flour
¾ cup graham cracker crumbs
1 cup old fashioned oats
1 tablespoon cornstarch
2 ½ teaspoons baking powder
½ teaspoon salt
1 cup Reese’s peanut butter baking chips
7 full-size Hershey’s chocolate bars
7 ounces marshmallow fluff
1 cup Reese’s miniatures chopped

Instructions

Preheat oven to 350°F (175°C). Line a 9×13 inch (23×33 cm) baking dish with parchment paper, allowing some overhang on the sides for easy removal, and set it aside.
In a large mixing bowl, cream together the melted butter and light brown sugar until light and fluffy. Add the creamy peanut butter and continue mixing until fully incorporated.
Beat in the eggs, one at a time, ensuring each egg is well combined before adding the next. Stir in the vanilla extract.
In a separate small mixing bowl, whisk together the all-purpose flour, graham cracker crumbs, old fashioned oats, cornstarch, baking powder, and salt until thoroughly combined.
Gradually add the dry flour mixture to the wet butter mixture, stirring slowly until just combined. Be careful not to overmix.
Gently fold in the Reese’s peanut butter baking chips.
Cover the cookie dough and refrigerate for at least 30 minutes. This chilling process helps the dough firm up and prevents excessive spreading during baking.
Press about two-thirds of the chilled cookie dough evenly into the bottom of the prepared baking pan.
Arrange the full-size Hershey’s chocolate bars over the cookie dough layer, breaking them into smaller pieces as needed to cover the surface.
Carefully spread the marshmallow fluff on top of the Hershey’s chocolate layer, creating an even coating.
Stir the chopped Reese’s miniatures into the remaining one-third of the cookie dough.
Drop spoonfuls of the remaining cookie dough mixture over the marshmallow layer. It does not need to be perfect or completely cover the fluff; the peeking marshmallow will caramelize beautifully.
Bake for 25-30 minutes, or until the top is golden brown and the marshmallow is toasted. Allow the bars to cool completely in the pan before lifting them out using the parchment paper overhang and cutting them into squares.

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