
So I came up with these cookies last summer when we got rained out of a camping trip. The kids were bummed about missing s'mores by the fire, and I had this random thought - what if I could make them in cookie form but kick them up a notch? I've always been a sucker for peanut butter with chocolate, so I figured why not throw that in the mix too. Honestly, these turned out way better than I expected. The cookies stay soft for days (unlike those graham crackers that get soggy two seconds after you make a s'more), and that filling is just ridiculous.
Made these for my daughter's school picnic last spring and it was almost embarrassing how many times this one dad came back for "just one more." He kept saying they were for his wife until she finally showed up looking confused because she hadn't tried a single one yet. Even the principal asked for the recipe - pretty sure that earned my kid some brownie points (or cookie points, I guess).
Key Ingredients
- Butter needs to be actually soft - not melted, not still cold with just the corners smooshed
- Peanut butter gives that nutty flavor throughout instead of just in the filling
- White sugar helps the cookies get that slight crispness around the edges
- Brown sugar keeps everything soft and adds that slight caramel-y flavor
- Eggs bind it all together - no weird substitutes here, just the real deal
- Vanilla extract because it makes literally everything taste better
- Flour provides the structure so these don't just melt into puddles
- Graham cracker crumbs are the secret weapon that makes these actually taste like s'mores
- Baking soda for that perfect rise without getting cakey
- Salt because without it, sweet stuff just tastes flat and one-dimensional

The Good Stuff Inside
- Mini marshmallows work way better than big ones - they melt just right without making a mess
- Chocolate chips - I like semi-sweet but milk works if that's your thing
- More peanut butter because why not double down on a good thing?
How It Happens
First, crank your oven to 350°F and line your cookie sheets. Nothing ruins good cookies faster than having them stick to the pan.
Beat the heck out of your butter, peanut butter, and both sugars. I mean really go to town - the fluffier this mixture gets, the better your cookies will be.
Add eggs one at a time, then vanilla. Don't rush this part or you'll end up with weird streaks.
In another bowl, mix all the dry stuff together. This seems like an unnecessary step but it makes sure the baking soda and salt get evenly distributed.
Gradually add the dry ingredients to the wet mixture. I usually do it in three batches so I don't end up wearing flour.
Scoop out dough balls about the size of a walnut. I flatten them slightly with my palm because they don't spread a ton on their own.
Bake till they're just barely golden - like 10-12 minutes. They'll look a little underdone in the middle, but that's what you want.
Let them cool completely. I know it's tempting to rush, but if you try to fill warm cookies, you'll have a melty disaster.
For the filling, microwave the chocolate chips and peanut butter in 30-second bursts, stirring in between until smooth.
Stir in those mini marshmallows while the chocolate's still warm enough to slightly melt them, but not completely.
Once it's cooled enough to thicken a bit, dollop it onto the flat side of one cookie and sandwich another on top.
My first attempt at these was a total disaster. I tried using big marshmallows cut into pieces, and they just oozed everywhere. I also originally tried putting graham cracker pieces in the dough instead of crumbs, which made the cookies break apart when you bit into them. Turns out the simplest approach worked best - using the crumbs in the dough gives that graham flavor without messing up the texture.
Serving Ideas
These are perfect just as they are, but if you want to get fancy, slightly warm them in the microwave for about 8 seconds before serving - it makes the filling all gooey again. I've served these alongside vanilla ice cream for dinner guests, and they went nuts for the hot-and-cold combination. They also look pretty stacked up on a cake stand if you're trying to impress people at a potluck.
Switch It Up
Sometimes I use crunchy peanut butter instead of creamy for a bit of texture. During the holidays, I've added a drop of peppermint extract to the chocolate filling which gives them this amazing thin-mint-meets-s'more vibe. If you're really feeling adventurous, try subbing Nutella for the peanut butter in the filling - my chocolate-hazelnut-obsessed friend nearly cried when I made these for her birthday.
Keep 'Em Fresh
Store these between layers of parchment paper in an airtight container. They'll stay good on the counter for about 3-4 days, though they rarely last that long in my house. Don't refrigerate them unless your kitchen is super hot - it makes the filling too hard. You can freeze the unbaked dough balls and just add a minute to the baking time when you're ready for a fresh batch.

I've made these cookies probably twenty times now, tweaking something small each time until they're just right. There's something about the combination of peanut butter, chocolate, and marshmallow that just works on a whole different level. My kids have started requesting these instead of birthday cake, and my husband has been caught eating them for breakfast when he thinks I'm not looking. Not that I can judge - I've definitely had one with my morning coffee more than once.
Frequently Asked Questions
- → Can I make these cookies ahead of time?
- Yes! The cookies themselves can be made 2-3 days ahead and stored in an airtight container. For best results, prepare the filling and assemble the sandwich cookies the day you plan to serve them, as the filling will soften the cookies over time.
- → What's the best way to store these sandwich cookies?
- Store assembled cookies in a single layer in an airtight container at room temperature for up to 3 days. If you need to stack them, place a sheet of parchment paper between layers to prevent sticking. They can also be refrigerated for up to 5 days, but bring to room temperature before serving.
- → Can I use natural peanut butter in this recipe?
- While natural peanut butter will work, it may change the texture of both the cookies and filling. For best results, use conventional creamy peanut butter (like Jif or Skippy) that doesn't require stirring, as it provides more consistent results in baking.
- → How do I get perfectly round sandwich cookies?
- For professional-looking sandwich cookies, use a round cookie cutter slightly smaller than your baked cookies to trim the edges immediately after taking them out of the oven while they're still soft. Alternatively, roll the dough into balls and flatten them with the bottom of a glass before baking.
- → Can I customize these cookies with different mix-ins?
- Absolutely! Try adding chopped peanuts to the cookie dough for extra crunch, swapping dark chocolate for milk chocolate in the filling, or using chocolate graham crackers instead of regular ones. You could also drizzle melted chocolate over the assembled sandwich cookies for an extra decadent touch.