Reese’s Peanut Butter S’mores Oatmeal Cookie Bars

I took all of my favorites and put them in these bars…outrageously awesome!

Reese’s Peanut Butter S’mores Oatmeal Cookie Bars – total indulgence in each bite!

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Reese's Peanut Butter S'mores Oatmeal Cookie Bars - total indulgence in each bite! |


Woohoo! Today is the start of S’mores Week! I have been SO looking forward to this week for so long because WE LOVE S’MORES!  I have thought of so many s’mores recipes over the past few weeks and it was crazy hard to narrow it down to just three but these bars definitely made the cut.  Unreal people.

I started with my Reese’s Peanut Butter Oatmeal Cookie Bars and got a little s’mores happy. I totally intended on going s’mores exclusively but, it’s SO hard for me to not include Reese’s :) And we all know peanut butter is s’mores BFF.

There were a couple of key changes that I made that really took this recipe over the top. I used graham cracker crumbs for part of the flour and while I was a tad bit skeptical at the time, I am now a total convert.  The graham crackers add such flavor and texture and they really made these cookie bars the ultimate s’mores treat.

The cookie dough has peanut butter as well as Reese’s peanut butter chips which makes these bars the perfect treat for peanut butter lovers. I kept the oatmeal in the recipe because I am a total sucker for oatmeal and just love how it really holds the cookie together.  Also? Then I can tell myself these bad boys are healthy – right?

Reese's Peanut Butter S'mores Oatmeal Cookie Bars - total indulgence in each bite! |

After pressing about two-thirds of the cookie dough into the dish, I started in on the chocolate.  LOTS of chocolate. Seven Hershey’s bars made their way on to that cookie dough and honestly, I could have stopped here.  But, no!  We need marshmallows!

Reese's Peanut Butter S'mores Oatmeal Cookie Bars - total indulgence in each bite! |

Marshmallow fluff is definitely the way to go here.  It was so easy to spread it all over the Hershey’s chocolate bars and then when it baked, the fluff started peeking through the cracks and got perfectly toasted – just like s’mores should be!

I mixed in some chopped up Reese’s miniatures into the remaining cookie dough and then dropped it by the teaspoonful on top of the marshmallow layer.  It took all of my willpower to keep from grabbing a spoon and just digging in at this point.

Down girl!

Reese's Peanut Butter S'mores Oatmeal Cookie Bars - total indulgence in each bite! |

A short trip to the oven yielded the most beautiful cookie bars I have ever seen…

Reese's Peanut Butter S'mores Oatmeal Cookie Bars - total indulgence in each bite! |

Glorious, right? I totally wanted to get pics when the chocolate was all ooey-gooey and melty but my schedule unfortunately was not on my side.  Check out that marshmallow though – perfection!

Reese's Peanut Butter S'mores Oatmeal Cookie Bars - total indulgence in each bite! |

Layer after layer of just sheer indulgence.  That Hershey chocolate bar layer is ridiculous – so rich and chocolatey – it totally makes you sit up and take notice.  The cookie bar layers sandwich all of the s’mores flavors and are a treat in and of themselves.

Reese's Peanut Butter S'mores Oatmeal Cookie Bars - total indulgence in each bite! |


Peanut Butter Smores Oatmeal Cookie Bars
Reese's Peanut Butter S'mores Oatmeal Cookie Bars - total indulgence in each bite!
Serves: 24 bars
  • 1½ sticks (12 Tbls) unsalted butter, melted
  • 2 c light brown sugar
  • ½ c creamy peanut butter
  • 2 eggs, room temperature
  • 1 Tbls vanilla
  • 1½ cups all-purpose flour
  • ¾ cup graham cracker crumbs
  • 1 c old fashioned oats
  • 1 Tbls cornstarch
  • 2½ tsp baking powder
  • ½ tsp salt
  • 1 c Reese's peanut butter baking chips
  • 7 full-size Hershey's chocolate bars
  • 7 oz jar marshmallow fluff
  • 1 cup chopped Reese's miniatures
  1. Preheat oven to 350 degrees.
  2. Line a 9x13 inch baking dish with parchment paper.
  3. Cream butter and sugar together in a large mixing bowl. Add peanut butter and continue mixing.
  4. Add eggs one at a time, mixing well after each egg. Add in vanilla.
  5. Combine flour, graham cracker crumbs, oats, cornstarch, baking powder, and salt in a small mixing bowl.
  6. Add the flour mixture to the butter mixture, slowly stirring until well combined.
  7. Stir in the peanut butter chips.
  8. Refrigerate cookie dough for at least 30 minutes.
  9. Spread ⅔ of the dough on the bottom of the pan.
  10. Top with Hershey's bars, breaking apart as needed.
  11. Spread marshmallow fluff on top of Hershey's bars.
  12. Stir chopped Reese's into remaining cookie dough.
  13. Drop the remaining dough on top by the teaspoon. It doesn't have to be perfect and it won't cover all the marshmallow fluff.
  14. Bake for 25-30 minutes. Let cool completely and then cut into bars.

Reese's Peanut Butter S'mores Oatmeal Cookie Bars - total indulgence in each bite! |

Love s’mores as much as I do? Check out all these other incredible s’mores recipes from my friends!


 More peanut butter madness:


Peanut Butter Caramel Toffee Chocolate Chip Cookie Bars


Peanut Butter Stuffed French Toast


Reese’s Peanut Butter Oatmeal Cookie Bars

Peanut Butter Candy Recipe

 Peanut Butter Candy

Trish Signature Block

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  1. I love that you went nutty here! Peanut butter chips and peanut butter cups with s’mores! Holy Reese’s! These are magnificent!
    Mir recently posted..Pink Velvet Cookies

  2. These bars look crazy good, Trish! I love the addition of the oatmeal so they’re nice and chewy, too. :)
    marcie recently posted..Fresh Mint Ice Cream with Mocha Ripple

  3. Oh my gosh! Look at all that chocolate in there! Love!
    Julianne @ Beyond Frosting recently posted..S’mores Lasagna

  4. Talk about DIVINE!!! This looks like the best s’more ever!
    [email protected] recently posted..Glazed Chocolate Zucchini Cake Donuts

  5. It’s like you took every baked good that I love and threw them all into one fabulous bar! They sound delicious! Pinned!
    Lindsey @ American Heritage Cooking recently posted..Soft Chewy Smores Crumble Bars

  6. Oh. My. GOSH Trish!! Do you have any left?? Any at all? Because I will seriously hop in my car this very second and take any leftovers you can give me. (I don’t live that far away!) They look incredible! All of that chocolate… And marshmallow… And Reese’s mini PB cups… Heaven. Just pure heaven. Pinning and dreaming of how awesome they taste!!
    Amy @ Amy’s Healthy Baking recently posted..Clean “Elvis” Peanut Butter Banana Cupcakes

  7. I swear I can smell them just by looking at those pics, YUM
    Heather @ French Press recently posted..Smore Cookies

  8. They look perfect! I LOVE the reeses added in! And the oatmeal totally = healthy. :)
    Lindsay @ Life, Love and Sugar recently posted..Smores Cheesecake

  9. Oh my goodness! Totally unhealthy but absolutely yummy!
    Laura @ Laura’s Culinary Adventures recently posted..Coconut and Almond No Churn Chocolate Ice Cream

  10. OMG- I love the pic of the 7 chocolate bars! Out of this world!
    Wendy | Around My Family Table recently posted..S’Mores Gooey Cake

  11. These look amazing, my mouth is drooling.
    Melissa @ The Alchemist recently posted..Fresh Peach Cobbler with a Biscuit Crust

  12. OH wow! Love the step by step photos too!
    Amber @ Dessert Now, Dinner Later! recently posted..In Search Of Contributors!

  13. Oh, my word! You know how much I love these bars right? All of my favorites in one amazing bar! Yup, I’m drooling!!!!
    Jocelyn @BruCrew Life recently posted..Oreo Pumpkin Gooey Bars

  14. These bars are totally crazy! Preeeeeetty sure I could make a meal outta these. No shame. ;) Pinned!
    [email protected] recently posted..Garden-Fresh Tomato Salsa

  15. Ok, ANOTHER recipe I gotta try to feed my peanut butter addiction. I think the only thing I’d change would be to use Special Dark as my chocolate.

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