These Brown Butter Fluffernutter Cookie Bars are rich, gooey, and packed with layers of flavor. Made with nutty brown butter, melty chocolate, peanut butter cookies, and a soft marshmallow center, they’re the ultimate indulgent dessert.
With crispy golden edges and a soft, chewy middle, every bite is loaded with texture and sweetness.
These Brown Butter Fluffernutter Cookie Bars are the perfect combination of rich, nutty flavor and gooey sweetness. Made with deeply caramelized brown butter, soft and chewy cookie dough, layers of marshmallow fluff, melty chocolate, and crunchy Nutter Butter cookies, this dessert delivers the ultimate texture and flavor in every bite.
The edges bake up golden and slightly crisp, while the center stays soft, thick, and irresistibly gooey. Perfect for parties, holidays, or anytime you’re craving a decadent homemade treat, these cookie bars are easy to make and guaranteed to impress.
Whether served warm for a melty, gooey experience or cooled for clean slices, these bars bring together nostalgic flavors with a gourmet twist.
In a saucepan over medium heat, melt the butter and continue cooking until it develops golden brown flecks and a nutty aroma, about 7 minutes.
Transfer to a measuring cup, add 1 tbsp of butter and place in the fridge to cool. The butter can be warm, but not hot.
In a large bowl, mix the brown sugar, granulated sugar, and cooled brown butter until combined.
Add eggs and vanilla, mixing until smooth.
In a separate bowl, whisk together flour, baking powder, and salt. Add to the wet ingredients and mix until almost combined.
Fold in chopped chocolate, chocolate chips, and crushed Nutter Butter cookies.
Line a 9x9 baking pan with parchment paper.
Press half of the cookie dough evenly into the bottom of the pan.
Spread the marshmallow fluff over the dough layer.
Top with the remaining cookie dough, spreading gently to cover.
Finish with extra crushed or whole Nutter Butter cookies on top.
Bake at 350°F (175°C) for 30–40 minutes, or until the edges are golden brown and slightly crispy.
The center should be set but still soft.
Allow the bars to cool before slicing for clean cuts.
Serve and enjoy the gooey marshmallow center and rich cookie layers.
Serve warm for extra gooey texture or at room temperature for cleaner slices. These pair perfectly with milk or coffee.
These Brown Butter Fluffernutter Cookie Bars are rich, nostalgic, and completely irresistible. The combination of peanut butter cookies, chocolate, and marshmallow fluff creates the ultimate dessert bar that’s guaranteed to impress.
Perfect for sharing—or not.
