Peanut Butter Lovers Fluffernutter Cookies
These soft and chewy fluffernutter cookies feature a rich, salty-sweet peanut butter dough wrapped around a gooey, molten marshmallow fluff center that stays perfectly soft even after cooling.
- Freezing the marshmallow fluff dollops prevents them from melting too quickly and escaping the cookie shell during baking.
- Conventional peanut butter provides the necessary structural fats to keep the dough from spreading into a greasy puddle.
- A touch of cornstarch in the flour mixture keeps the cookie crumb ultra-soft and chewy for days.
My first apartment had a kitchen the size of a closet, and it was there that I first tried to stuff marshmallow fluff inside a peanut butter cookie dough ball.
It exploded.
I spent three hours scraping caramelized sugar off the oven floor until my fingernails were raw.
Think about this in terms of physics: marshmallow fluff is an unstable foam of egg whites and sugar syrup, meaning that when it hits the thermal mass of a hot oven, the air pockets expand rapidly and the sugar liquefies, bursting through the weak protein matrix of standard cookie dough. I tried using a fancy, organic oil-separating brand once, and it failed spectacularly because the excess oil turned the dough into a greasy puddle.
Trust me on this one: the simple fix is freezing dollops of fluff before wrapping them in a dough made with conventional, emulsified peanut butter. If you love the classic chocolate-peanut butter combo, you should also try our peanut butter brownie swirl cookies.
Let's bake.
Irresistibly Soft and Chewy Fluffernutter Cookies for Peanut Butter Lovers
Ingredients
- 1/2 cup marshmallow fluff
- 1/2 cup unsalted butter, softened
- 3/4 cup conventional creamy peanut butter (such as Jif or Skippy)
- 1/2 cup packed light brown sugar
- 1/4 cup granulated sugar
- 1 large egg, room temperature
- 1 teaspoon vanilla extract
- 1 1/2 cups all-purpose flour
- 1 teaspoon cornstarch
- 1/2 teaspoon baking soda
- 1 teaspoon Diamond Crystal kosher salt (or 1/2 teaspoon fine sea salt)
Directions
- Line a small tray with parchment paper. Drop 12 rounded teaspoons of marshmallow fluff onto the tray and freeze for at least 30 minutes until firm.
- Preheat your oven to 350°F (175°C) and line two large baking sheets with parchment paper.
- In a large bowl, beat the softened butter, conventional peanut butter, brown sugar, and granulated sugar together until light and fluffy, about 2 to 3 minutes.
- Add the egg and vanilla extract, beating until fully incorporated and smooth.
- In a separate bowl, whisk together the all-purpose flour, cornstarch, baking soda, and Diamond Crystal kosher salt.
- Gradually add the dry ingredients to the wet ingredients, mixing on low speed just until the dough comes together. Do not overmix.
- Divide the dough into 12 equal portions. Flatten each portion into a disc, place a frozen dollop of marshmallow fluff in the center, and wrap the dough completely around the fluff, pinching the seams tightly to seal.
- Place the dough balls on the prepared baking sheets, leaving at least 2 inches of space between each cookie.
- Bake for 10 to 12 minutes, or until the edges are lightly golden. The centers should still look soft.
- Allow the cookies to cool on the baking sheet for 10 minutes before transferring them to a wire rack to cool completely.
Notes
- Brand Recommendation: Use Diamond Crystal kosher salt. If you only have Morton's kosher salt or fine table salt on hand, cut the volume in half (use 1/2 teaspoon) to prevent the cookies from tasting overly salty.
- Science-Backed Rationale: Conventional peanut butter contains hydrogenated vegetable oils that stabilize the fat emulsion. Natural peanut butters will separate during baking, causing the cookies to spread into greasy puddles.
- Preemptive Workflow Warning: Do not skip freezing the marshmallow fluff dollops. If they are not rock-hard when you wrap the dough around them, the fluff will dissolve into the dough and burn on your baking sheet.
- Storage Behavior: After a day in an airtight container, the moisture from the marshmallow core will migrate into the surrounding cookie crumb, making them even softer and chewier than when fresh.
Serving Suggestions
These cookies are best enjoyed slightly warm when the marshmallow center is at its absolute peak of gooeyness. Pair them with simple, classic treats to balance the rich peanut butter flavor.
- Serve warm with a tall, cold glass of whole milk.
- Pair with a scoop of vanilla bean ice cream to create a warm-and-cold dessert plate.
- Drizzle with a bit of warm chocolate ganache right before serving.
- Enjoy alongside a hot cup of black coffee to cut through the intense sweetness.
- For a fun twist, try them alongside our quick peanut butter protein bites for a double dose of peanut flavor.
Storage and Reheating
Store these cookies in an airtight container at room temperature. They actually improve after twenty-four hours because the marshmallow moisture migrates into the cookie crumb.
Do not refrigerate them.
The cold temperature of a fridge recrystallizes the starches in the flour, turning your beautifully soft cookies into dry, crumbly pucks. If you must keep them longer than three days, freeze them in a single layer on a baking sheet before transferring them to a zip-top bag where they will keep perfectly for up to three months.
To reheat, simply microwave for eight seconds.
This softens the marshmallow core without melting the cookie.
Ingredient Substitutes
If you need to swap out a few ingredients, these reliable alternatives will keep your cookies tasting fantastic:
- Marshmallow Fluff: You can use large marshmallows cut in half, though they won't melt quite as seamlessly as the fluff.
- Creamy Peanut Butter: Crunchy conventional peanut butter works perfectly if you want an added textural crunch.
- Diamond Crystal Kosher Salt: Use half the amount of fine sea salt or table salt if that's what you have on hand.
- Cornstarch: Arrowroot powder can be substituted in an equal ratio to maintain that tender crumb.
Go ahead and make a mess in your kitchen—it is entirely worth it.
Susan Rosie
I've spent over 12 years perfecting recipes so you can cook with confidence. Every dish on Storied Skillet is tested multiple times – because your dinner matters. I believe in simple ingredients, clear instructions, and big flavors.
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