Homemade Peanut Butter Marshmallow Cookies

Pulling a fresh sheet of these peanut butter marshmallow cookies out of the oven brings an immediate rush of nostalgic comfort. The air fills with the deeply roasted, nutty aroma of warm peanut butter coupled with the caramelized, sweet scent of toasted marshmallows. Each cookie boasts a thick, chewy edge with a center that pulls apart into gooey ribbons of melted marshmallow fluff.

Whenever I bake a batch on a rainy afternoon, my kitchen island quickly becomes the central hub for my family. My kids love watching the mini marshmallows puff up and turn golden-brown under the oven light, while my husband is always first in line to grab one while the center is still warm and molten. It is the perfect sweet treat that elevates a classic childhood flavor combination into an incredibly decadent, bakery-quality cookie.

Why You’ll Love It

• Nostalgic flavor profile: Recreates the classic, beloved “fluffernutter” taste profile in a warm, elevated homemade baked good format.
• One-bowl cleanup: The entire cookie dough comes together in just a single mixing bowl, saving you precious cleanup time.
• Sensational texture pairing: Combines the dense, nutty chewiness of a peanut butter base with soft, gooey marshmallow pockets.
• Perfect bake time: Bakes completely in under ten minutes, letting you satisfy your intense sweet tooth cravings almost instantly.
• Simple pantry staples: Uses basic ingredients you likely already have on hand without requiring any special shopping trips.

Ingredient Notes & Details

• Creamy peanut butter: Provides the rich, nutty foundation and structural fats for the dough. Swap: Almond butter works as an excellent alternative.
• Mini marshmallows: Melt during the bake to create gooey pockets of sweet, sticky chewiness. Swap: Chopped large marshmallows can be used.
• Dark brown sugar: Packed tightly to introduce moisture and a deep molasses undertone, ensuring the cookie center stays soft.
• Unsalted butter: Adds a classic creaminess that keeps the crumb tender. Swap: Softened coconut oil provides a dairy-free option.
• All-purpose flour: Gives the cookies their structure and holds the heavy marshmallow pockets in place.

Step-by-Step Instructions

Start by creaming your softened unsalted butter, creamy peanut butter, and brown sugar together in a large bowl. Beating these ingredients thoroughly incorporates air into the fats, which prevents your final cookies from baking up flat, dense, or greasy. Next, add your egg and vanilla extract, mixing until the batter looks pale and fluffy.

Gradually fold in your flour, baking soda, and salt. Stir just until the flour disappears to keep the gluten relaxed, guaranteeing a tender, soft crumb. Gently fold in your mini marshmallows, distributing them evenly throughout the thick dough so every single cookie gets a balanced ratio of nutty dough and gooey sweetness.

Scoop the dough into uniform balls and space them evenly onto a parchment-lined baking sheet. Baking them at a high temperature forces the edges to set quickly into a chewy crust while the interior marshmallows turn beautifully molten. Watch them closely near the end; as the marshmallows expand, they form gorgeous caramelized webbing around the golden cookie edges.

Expert Tips

• Use standard commercial peanut butter; natural oil-separated varieties cause excessive spreading.
• Use parchment paper because melted marshmallows will stick tightly to bare metal.
• Tuck exposed marshmallows inside the dough balls to prevent them from burning.
• Swirl a round cookie cutter around hot cookies to shape them.
• Let cookies cool on the pan for five minutes to set properly.

Storage & Reheating

Store these cookies in an airtight container at room temperature for up to three days. To keep them incredibly soft, drop a slice of plain white bread into the container to balance the moisture. Microwave a cookie for 8 seconds before enjoying to recapture that fresh, gooey, pull-apart magic.

Serving Ideas & FAQs

Pair these rich, sweet cookies with a tall glass of ice-cold milk, a hot cup of black coffee, or a scoop of vanilla bean ice cream.

Why did my marshmallows melt away and leave holes? Marshmallows on the bottom touching the hot pan will melt into caramel lace. Tucking them into the center protects them.

Can I use chunky peanut butter? Yes. Chunky peanut butter adds a lovely crunchy texture contrast to the soft marshmallows.

Homemade Peanut Butter Marshmallow Cookies

Prep Time: 15 minutes

Bake Time: 9 minutes

Total Time: 24 minutes

Servings: 18 cookies

Ingredients

• ½ cup unsalted butter, softened
• ¾ cup creamy peanut butter
• 1 cup dark brown sugar, packed
• 1 large egg
• 1 teaspoon vanilla extract
• 1 ¼ cups all-purpose flour
• ½ teaspoon baking soda
• ¼ teaspoon salt
• 1 cup mini marshmallows

Instructions

1. Preheat your oven to 350°F and line a baking sheet with parchment paper.
2. In a large bowl, cream together the softened butter, peanut butter, and brown sugar until fluffy.
3. Whisk in the egg and vanilla extract until completely smooth.
4. Fold in the flour, baking soda, and salt just until a thick dough forms.
5. Gently fold in the mini marshmallows until evenly distributed.
6. Scoop into 18 uniform balls, tucking any exposed marshmallows inside the dough.
7. Arrange on the baking sheet and bake for 9 minutes until the edges are golden. Cool on the pan for 5 minutes.