
Soft and chewy graham cracker brown sugar cookie bars filled with peanut butter cups and marshmallow cream.
Excuse me while I do a little happy dance.
These bars are everything you could ever want them to be: gooey, chewy, melty, buttery, brown sugary, sweet, graham crackery.

I love s’mores, they take me back to summers spent hiking, playing, swimming in the cold lake as the sun rose, and roasting marshmallows over an open fire. I love a burnt marshmallow — the product of impatience, but still so good.
With two young boys running around, I’m not all about open flames just yet. But I couldn’t wait to share the summery deliciousness that are s’mores with them. Peanut butter cup s’mores cookie bars to the rescue. They’re a great travel and toddler-friendly alternative to a staple campfire treat.

I can’t decide which part is my favorite:
- Gooey, sticky marshmallow
- Soft, buttery, brown sugary graham cracker cookie bar
- Melty peanut butter chocolate cups
Pro tip — eat these warm to get the full effect. Another tip for all the chocolatey cookie bar lovers out there — don’t miss my Oatmeal Chocolate Chip Cookie Bars, another reader favorite that makes me weak in the knees.
When you make them, snap a photo and tag @anotherroot on Instagram — I’d love to see!

Peanut Butter Cup S’mores Cookie Bars
Equipment
- 8×8 baking dish
- Hand mixer or stand mixer with paddle attachment
Ingredients
- 1/2 cup salted butter, room temperature
- 3/4 cup packed light brown sugar
- 1 tsp vanilla extract
- 1 large egg
- 1 cup all purpose or white whole wheat flour
- 1 cup graham cracker crumbs 8-9 crackers
- 1/2 tsp baking powder
- 6 Reese's peanut butter cups (or brand of choice), chopped up into small pieces
- 1 cup marshmallow cream don't use marshmallows
Instructions
- Preheat the oven to 350 degrees and line an 8×8 baking dish with aluminum foil, so that it goes up and over the sides — this will make it much easier to get the bars out of the pan to cut later.
- In a large bowl, add the butter and brown sugar. Use a hand mixer (alternatively, you could use a stand mixer with the paddle attachment) to cream the butter and sugar together on medium speed, for about 2 minutes. Add the vanilla and egg, beating until combined.
- Add the flour, graham cracker crumbs and baking powder to the bowl, and with the mixer on low, gently combine.
- Press ⅔ of the cookie dough into the bottom of your prepared pan. Spread the marshmallow cream evenly over the cookie dough and sprinkle with the chopped Reese’s Peanut Butter Cups. Break the remaining cookie dough up over the top and mold into a flat layer — it won’t fully cover and that’s okay.
- Bake for 25 minutes, or until the top is golden brown. Remove from the oven and cool completely on a wire rack before removing from the pan. Cut into squares and enjoy!
- Store at room temperature in a sealed container for up to a week. If storing in the refrigerator, I’d recommend microwaving for 15-20 seconds to warm them through and turn the marshmallow cream gooey again.
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