Peanut Butter S’mores Bars Recipe – Chewy Chocolate Graham Squares

Imagine s’mores transformed into a bar — gooey peanut butter s’mores bars capture everything you love about the classic treat. A graham-cracker-studded chocolate chip cookie base is layered with marshmallow fluff, broken graham crackers, and extra chocolate for pockets of melty goodness. They’re the perfect no-campfire substitute for summer dessert.

Can you believe it’s already August? Summer seems to fly by. With no campfires this year because of wildfires and rain, these bars bring the campfire s’mores experience to your kitchen.

The dough comes together in one bowl and is straightforward to make. It features browned butter, creamy peanut butter, chocolate chips, and graham cracker crumbs for that unmistakable s’mores flavor.

If you haven’t combined peanut butter with s’mores before, you’re missing out — it makes the bars rich, nutty, and extra satisfying.

Once the cookie dough is ready, press most of it into an 8×8 pan, spread marshmallow fluff over the layer, sprinkle with chocolate chips and broken graham crackers, and finish with the remaining dough to seal everything in.

Ingredients Notes

Key ingredients used in this recipe. Exact amounts are in the recipe card below.

• Unsalted butter — melted and browned to add a deep, nutty flavor.
• Chocolate chips — semi-sweet is recommended, but milk, dark, or white can be used. You can also chop a chocolate bar for extra melty pockets.
• Eggs — use one whole egg and one egg yolk at room temperature for the best texture.
• All-purpose flour — forms the cookie base.
• Graham crackers — crumbs are mixed into the dough and broken pieces are layered inside the bars for texture and flavor.
• Marshmallow fluff — store-bought marshmallow fluff (or marshmallow creme) is essential; regular marshmallows don’t spread the same way and won’t produce the same ribbons inside the bars.
• Peanut butter — creamy or chunky works; avoid runny natural peanut butter since it can affect the dough’s consistency.

Step-by-step instructions

These peanut butter s’mores bars bake in an 8×8 square pan. Line the pan with parchment paper on the bottom and two sides for easy removal. You’ll need a large mixing bowl, spatula, and whisk.

Step 1 — Prep: Preheat the oven to 350°F (180°C). Grease the pan and line it with parchment paper on the bottom and two sides, then grease the parchment.

Step 2 — Brown the butter: Melt the butter in a pan over medium heat, stirring as it foams and browns. When it becomes golden and fragrant, remove from heat and let it cool for about 20–30 minutes (don’t let it solidify).

Step 3 — Mix wet ingredients: In a large bowl, combine the cooled browned butter, brown sugar, and peanut butter. Whisk in the egg, egg yolk, and vanilla until the mixture is light and fluffy.

Step 4 — Add dry ingredients: Fold in graham cracker crumbs, flour, baking soda, baking powder, and salt with a spatula until a soft cookie dough forms.

Step 5 — Chocolate chips: Stir in about 3/4 cup of the chocolate chips into the dough, reserving the rest for the topping.

Step 6 — Fill the pan: Press about three-quarters of the dough evenly into the prepared pan so the entire bottom is covered.

Step 7 — Layer marshmallow and toppings: Spoon and spread the marshmallow fluff evenly over the dough — small spoonfuls help it spread more easily. Sprinkle the remaining chocolate chips and broken graham crackers on top. Flatten and distribute the remaining dough over the surface in pieces, leaving gaps so marshmallow ribbons peek through.

Step 8 — Bake: Bake for 25–30 minutes, until the edges are lightly golden. The marshmallow may puff up during baking but will settle as the bars cool.

Slice into squares and enjoy warm for the gooeyest texture. These bars are best within three days of baking.

FAQ

Can I use regular marshmallows instead of marshmallow fluff?

No — in testing, whole marshmallows didn’t spread enough and mini marshmallows spread too much. Marshmallow fluff (creme) gives the ideal ribboned texture.

Is marshmallow creme the same as marshmallow fluff?

Yes — they’re the same product with different regional names.

Can I eat these warm?

Absolutely. They’re meant to be gooey — warming a piece in the microwave for a few seconds enhances that campfire feel.

Can I double this recipe?

Yes. Double the ingredients and bake in a 9×13 pan; check doneness at about the same bake time but monitor until edges are lightly golden.

Storing & Freezing

Store the bars at room temperature in an airtight container for up to 3 days.

Freeze cooled bars in an airtight container or zip-top bag for up to 1 month. Reheat individual squares briefly to restore gooeyness.

My favorite way to enjoy them is warm — they taste like a campfire s’more without leaving home.