Peanut Butter S’mores Bars
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The only thing better than s’mores might just be these peanut butter s’mores bars! Chewy peanut butter graham cookie dough with milk chocolate, more peanut butter and gooey marshmallow in the middle. These bars are so simple to make and the perfect combo of peanut butter and s’mores.
These peanut butter s’mores bars are the sister recipe to my s’mores cookie bars. The recipe starts with chewy peanut butter cookie dough, where some of the flour is replaced with graham crumbs for the classic s’mores flavor. In the middle, there’s a thick layer of milk chocolate, peanut butter, and then gooey marshmallow. The peanut butter cookie dough acts as the graham crackers do in a traditional campfire s’more.
Making Peanut Butter S’mores Bars
For this recipe, you’ll start by making the peanut butter graham cookie dough. It’s incredibly simple and there’s no mixer required. You’ll first whisk together melted butter, peanut butter and brown sugar – then whisk in the egg, an additional egg yolk and vanilla extract. The flour and salt are stirred into the dough until there are no lumps, then you’ll fold in the graham crumbs.
Then it’s time to assemble and bake the bars.
- Scoop out about 1 cup of peanut butter graham cookie dough – this is saved for the topping.
- Press the remaining cookie dough into the bottom of a lined 8×8 inch pan to create an even layer.
- Place a layer of chocolate on top of the cookie dough. Press it down slightly. I used whole chocolate bars.
- Spread a layer of peanut butter on top of the chocolate. Microwaving the peanut butter for about 30 seconds on medium power first, then giving it a stir make for easier spreading.
- Spread a layer of marshmallow fluff on top of the peanut butter. Again, I recommend microwaving it for about 30 seconds on medium power first for easier spreading.
- Form the reserved 1 cup of cookie dough into round discs and place on top of the marshmallow layer. You want to try and cover most of the marshmallow, but it’s OK if some peeks through.
- As the bars bake, any marshmallow that’s visible will puff up – creating pools and dollop of goo. If the marshmallow layer is entirely covered, then you’ll have a more even layer of marshmallow in the middle.
- The bars then bake in the preheated oven for about 30-35 minutes, or until the top is golden.
Recipe Tip
If you let the bars cool for at least 8 hours, then you’ll end up with cleaner cuts. If you cut these while warm – they’ll be super gooey and you’ll need a spoon to eat them with. I waited about 4 hours before slicing these bars for the photographs – they were still gooey, but they held together and I didn’t need a spoon.
An Important Note About Marshmallow Fluff
In this recipe, marshmallow fluff – AKA marshmallow creme – cannot be substituted with regular marshmallows. When marshmallows bake in the oven for an extended period of time, they will melt into the cookie layer and create a hard, sticky bar with no marshmallow layer in the middle.
More S’Mores Treats to Love
- Easy S’mores Bars – graham crust, thick layer of chocolate, and marshmallows on top
- Golden Graham S’mores Bars
- S’mores Cookie Bars
Peanut Butter S’mores Bars
Equipment
- 8×8 inch (20×20 cm) pan
Ingredients
Peanut Butter Graham Cookie Dough
- ½ cup unsalted butter (112 grams) , melted
- ¼ cup smooth peanut butter (about 65 grams)
- ¾ cup brown sugar (158 grams), I recommend using light brown sugar
- 1 large egg
- 1 large egg yolk, in addition to the whole egg
- 1 teaspoon vanilla extract
- 1½ cup all-purpose flour (188 grams)
- ¼ teaspoon salt
- ½ cup graham crumbs (about 50-60 grams), about 4-5 sheets of graham crackers
Filling Ingredients
- 2 XL Hershey's Milk Chocolate Bars , or 3-4 100 gram bars for those in Canada, or 1½ cups chocolate chips
- ½ cup smooth peanut butter (about 130 grams)
- 1¼ – 1½ cups marshmallow fluff, AKA marshmallow creme
Instructions
- Preheat the oven to 350℉ (180℃). Line an 8×8 inch (20×20 cm) square baking pan with parchment paper, leaving an overhang around the sides.
Make the Peanut Butter Graham Cookie Dough
- In a medium bowl, whisk together the melted butter, peanut butter and sugar. When finished, there should be no lumps of brown sugar and the melted butter shouldn't sit on top of the sugar.
- Whisk the egg, additional egg yolk and vanilla extract into the butter mixture until you no longer see pieces of egg.
- Stir in the flour and salt. Keep stirring until there are no lumps of flour.
- Stir in the graham crumbs.
Assemble & Bake
- Scoop out about 1 cup of cookie dough. Save this dough – it's used for the top layer later.
- Press the remaining dough into the bottom of the prepared pan, creating an even layer.
- Place a layer of chocolate on top of the cookie dough and press down slightly. You will need to break your chocolate bars in order to get the base completely covered, depending on their size.
- Microwave the peanut butter in a a heatproof bowl for about 30-45 seconds on medium speed. Stir the peanut butter until smooth, then spread over top of the chocolate layer. Microwaving first makes it easier to spread on top of the chocolate.
- Measure out the marshmallow fluff, add to a heatproof bowl and microwave for 30-45 seconds on medium power. Spoon the marshmallow fluff over the peanut butter layer and spread into an even layer. Again, microwaving the fluff first makes spreading it much easier.
- With the reserved 1 cup of cookie dough, form into flat discs and place on top of the marshmallow layer. You don't need to have all of the marshmallow covered, but try not to have too large of exposed areas.
- Bake in the middle of the preheated oven for about 30-25 minutes, or until the peanut butter cookie dough on top looks set and is golden brown. The marshmallow will have started to fluff up where it is exposed.
- Cool the bars in the pan. For clean cuts, the bars need to be completely cooled. When ready to slice, lift the bars out of the pan using the overhang of the parchment paper and place on a cutting board. Cut with a sharp knife. If the bars are still warm, they will fall apart. They will be deliciously gooey, but you'll need to eat them with a spoon.
Notes
- Peanut Butter: Use smooth peanut butter, which doesn’t separate. Using peanut butter where the oil sits on top can lead to inconsistent results.
- Marshmallow Fluff: This recipe requires marshmallow fluff/marshmallow creme. Do not use regular marshmallows as they will melt into the cookie layer, leaving you with no marshmallow in the middle. You will use about 1/2 of a 16 ounce jar of fluff.
- Chocolate Bars: If you want the entire base covered, I bought four 100 gram Hershey’s Bars. I didn’t need to use the entire 4th bar. The sizes of Hershey’s bars vary in different countries – so depending on where you are, the number of bars you will need will be different.
- Nutrition: Details are an estimate only based on 1 bar, assuming the pan is sliced into 12 uniform bars.
- Storage: Store in an airtight container at room temperature for up to 5 days.
