These Peanut Butter S’mores Cookie Bars are made with a chewy, graham cracker infused peanut butter cookie base, are loaded with pockets of melty mini marshmallows, and decorated with real milk chocolate bar pieces!
These peanut butter s’mores cookie bars are a rare recipe of mine that turned out absolutely perfectly on the first try.
It almost never happens that I like a recipe enough the very first time I make it that I don’t feel the need to make it again, tweaking this and that trying to improve the flavor or chewiness or whatever I have in my mind at the moment that needs improvement. Case in point: my homemade brownies took approximately 27 tries and 8 months to get just right. Despite this, these cookie bars didn’t even make it to my photography studio (AKA my living room) and I ended up having to make them again, anyway, just so that I could take pictures.
I’d mostly like to blame Zach for eating half the pan before they even finished cooling, but since I ate the other half I don’t think that would be entirely fair. They’re undoubtedly addictive, and totally delicious, and I think you’re going to enjoy them just as much as we did.
Self control, what is that, anyway?
Here’s what I love about these peanut butter s’mores cookie bars, and what I think you’re going to love about them, too.
- Subtle graham cracker flavor that complements the peanut butter perfectly 👌🏼
- Soft and chewy peanut butter cookie base! Not only is the cookie layer already soft on its own, but all those mini marshmallows that you’re going to fold into the batter are going to melt away as they bake creating gooey tunnels of chewy marshmallow goodness (and a lightly crisp, crackly top wherever the marshmallows touch the surface of your cookie bars). It’s absolutely heaven. Yum. I’m so hungry right now.
- Real Hershey bars for that authentic s’mores flavor. Sure, you could use milk chocolate chips but real s’mores flavor calls for real s’mores ingredients, so grab yourself 4 Hershey bars, maybe make it 5 because if you’re anything like me you’re going to eat a whole candy bar’s worth while you’re chopping them up, anyway.
Tips for Making Peanut Butter S’mores Cookie Bars
I swear I didn’t mean to make this post just a bunch of bullet points, but let’s talk tips now.
- Crunchy or creamy peanut butter will work in this recipe, but I don’t recommend using a natural peanut butter.
- This batter is thick, so thick that I actually broke one of my favorite spatulas trying to stir in the marshmallows and chocolate by hand. The milk does help thin it out a bit, just beware that it’s going to take a little muscle if you want to stir the add-ins by hand, and it may be too thick even for an electric hand mixer.
- I recommend using a metal pan when baking simply because that’s what I’ve used and tested. A glass pan will work, but it will likely take your cookie bars longer to finish baking.
- As with my cookie bar and brookie recipes I always opt for my baked goods to be just slightly under-baked when pulling them out of the oven. I recommend using a toothpick and looking for a few moist crumbs (not wet batter, just fudgy crumbs) on the toothpick rather than waiting for a completely clean one to indicate it’s done. The peanut butter s’mores bars will finish cooking as they cool, and pulling them out before they’re completely baked through helps to keep them soft and chewy.
Enjoy!
More Recipes To Try:
- S’mores Cereal Bars
- Cookie Cake
- Peanut Butter Shortbread Bars
- Peanut Butter Chocolate Chunk Cookies
- Peanut Butter Fudge Stuffed Brownies
Peanut Butter S'mores Bars
Ingredients
- 1 cup unsalted butter softened (227g)
- 1 cup creamy peanut butter I don't recommend using natural peanut butter (235g)
- 1 cup light or dark brown sugar tightly packed (200g)
- 1 cup granulated sugar (200g)
- 1 large egg + 1 large egg yolk
- 1 ½ teaspoons vanilla extract
- 1 ¾ cups all-purpose flour (345g)
- ½ cup graham cracker crumbs (65g)
- 1 teaspoon baking powder
- 1 teaspoon cornstarch
- ½ teaspoon salt
- 2 Tablespoons milk
- 4 1.55 oz milk chocolate Hershey bars chopped into pieces*
- 1 ½ cups mini marshmallows (72g)
Instructions
- Preheat oven to 350F (175C) and line a 13x9 metal pan with parchment paper or grease and flour the sides and bottom of the pan.
- Combine butter, peanut butter, and sugar in a large bowl and use an electric mixer to beat until light, creamy and well-combined.
- Add egg/egg yolk and vanilla extract, and stir well.
- In a separate bowl, whisk together flour, graham cracker crumbs, baking powder, cornstarch, and salt.
- Gradually, on low speed, add flour mixture to peanut butter mixture, pausing occasionally to scrape down sides of bowl.
- Add milk and stir until combined.
- Fold in chopped Hershey bars and mini marshmallows -- the batter will be thick (I broke a spatula stirring it so proceed with caution!).
- Spread batter into prepared ban and bake on 350F (175C) for 25-28 minutes (toothpick inserted in center should come back mostly clean with only a few crumbs)
- Allow to cool completely before cutting and serving.
Notes
Nutrition
Nutritional information is based on third-party calculations and should be considered an estimate only. Actual nutritional content will vary based upon brands used, measuring methods, cooking method, portion sizes, and more.
Alison Jakubowski
This looks like an amazing recipe that I know my family will love! One question: could I use chocolate chips instead of broken Hershey bars and still have good results? I have lots left over from Christmas and would like to use them up. Love your recipes always a hit!
Emily @ Sugar Spun Run
You sure can, Alison 😊 Enjoy!
Paige Larson
This turned out GREAT but I definitely needed to bake it so much longer then listed. So I did that the second time I made these. The first time they were underdone in the center, but some people like that.
Not sure why it’s taking so long to bake? I use NordicWare 9X13 pan that I line with parchment. I only use this blog for all of my recipes…the one thing is that I cannot find mini marshmallows as in the type that you’ll find in hot cocoa packets which is the size that looks like is used in the pictures. I can only find the mini marshmallows that you’d add to your hot cocoa (like 1/4 of a traditional marshmallow) Wondering if that makes a bit of a difference since those are gooey-er in nature?
Sam
The bigger marshmallows could be causing them to be gooey-er for sure. It can be tough to find those mini dehydrated marshmallows. I can normally find them near the hot chocolate. I’m not sure why yours are taking longer to bake, but I’m glad you’ve got it figured out. 🙂
CM
hi, how do we store this and how long does it last?
Sam
These will last for about a week at room temperature in an air tight container. 🙂
Trish
I want to start by saying I never comment on recipes, ever. I bake all the time, and have tried literally hundreds of recipes from Pinterest. I have to say there are no words to describe how delicious and easy these bars are. I made them for a coworker’s birthday, and will be making them again…and again…
Sam
Thank you so much, Trish! I appreciate you taking the time to leave a comment. I’m so glad you enjoyed them so much. 🙂
nad
good
Maricela
Hi Sam, wanted to ask if it’s okay to not incorporate the peanut butter in this recipe, my daughter is allergic. Is there a similar recipe and will it come out okay if I don’t use it? Thanks!
Sugar Spun Run
Hi, Maricela! This recipe is a peanut butter cookies base so I do not reccomend it. I have a S’mores Cookies recipe that I would use instead. You can bake the dough into cookies or into cookie bars if you’d prefer. There is no peanut butter in that recipe. 🙂
Aticle
sooo delicious can not stop eating it ,i made them for a project but i ate sooo much it remained only 2 but i got an A instead of an A* ,bummer,but i am still obsessed with it.*^_^*
Sam
😂 I’m so glad you enjoyed them! 🙂
Joanne J Woodman
Sam,wow I made these for work. They couldn’t eat them fast enough. Great recipe. Thanks Joanne
Sam
I am so glad everyone enjoyed them Joanne! Sounds like you’ll be the new favorite at work! 😉
Priscila
Just wondering, why not use natural peanut butter?
Can’t wait to try making these!
Sam
It could make them come out dry and crumbly.
Adelaide Gantt
I am already a subscriber but do not have the cookie e-book.
Sam
Hi Adelaide! I’m not sure why you didn’t get it when you subscribed, but I just e-mailed you the e-book!