If you grew up loving the classic Fluffernutter sandwich that blissful combination of peanut butter and marshmallow fluff then prepare for your new favorite dessert! These Fluffernutter Brownies take the rich, fudgy texture of homemade brownies and swirl them with creamy peanut butter and sticky, sweet marshmallow fluff for an easy, decadent treat that is absolutely addictive.
These brownies offer the ultimate nostalgic indulgence: a moist, fudgy chocolate base topped with distinct, delightful ribbons of salty peanut butter and sugary marshmallow fluff.
Recipe Details
- Flavor Profile: A rich harmony of salty, nutty peanut butter, intense sweet marshmallow fluff, and deep chocolate from the brownie base.
- Textures: Fudgy and dense, contrasted by the gooey, slightly chewy marshmallow fluff swirls that bake right into the top layer.
- Total Time: Minimal active prep time (about 15 minutes), as the base is a boxed mix, followed by a fast bake time of 20–30 minutes.
- Difficulty Level: Very Easy this recipe uses a boxed mix and relies on simple microwave steps and gentle swirling, making it perfect for a quick project.
What You’ll Need
This recipe simplifies the baking process by utilizing a boxed brownie mix as the foundation. The magic happens with just two key additions: creamy peanut butter and marshmallow fluff, which are gently melted and swirled over the batter before baking to create that iconic Fluffernutter flavor profile.
Ingredient Notes
- Boxed Brownie Mix – Any standard 9×9 inch brownie mix will work perfectly here. Follow the directions on the box exactly for mixing the batter to ensure a fudgy base.
- Creamy Peanut Butter – Choose a creamy, conventional peanut butter (like a processed brand) rather than a natural, oil-separated variety. The creamier type melts and swirls more smoothly, giving you beautiful ribbons of flavor.
- Marshmallow Fluff – This provides the sweet, sticky component of the Fluffernutter. Heating it briefly in the microwave is crucial to make it pliable enough for easy swirling.
Add-ins and Substitutions
These brownies are perfect as they are, but here are a few fun and simple ways to customize them:
- Nutty Crunch: Sprinkle a handful of chopped peanuts or walnuts over the top of the swirls before baking for added crunch and texture.
- Chocolate Chips: Fold a 1/2 cup of chocolate chips or chocolate chunks into the brownie batter for an extra layer of chocolate richness.
- Sea Salt Finish: After the brownies come out of the oven, immediately sprinkle a tiny pinch of flaky sea salt over the top to enhance the contrasting sweetness of the fluff and chocolate.
How to Make Fluffernutter Brownies
This recipe moves quickly! The main steps are prepping the brownie batter and then preparing the swirls. It’s important not to over-swirl the toppings so you can see those beautiful ribbons of flavor.
- Prepare the Pan and Batter: Preheat your oven to 350°F. Line a 9×9 inch baking pan with parchment paper, ensuring the paper covers all sides for easy removal. Prepare the brownie batter according to the directions specified on the box. Pour the prepared batter into the parchment-lined pan and use a rubber spatula to spread it into an even layer.
- Prepare the Swirls: Place the 1/3 cup of creamy peanut butter in a microwave-safe bowl and heat for 30 seconds until it’s melted and easy to drizzle. In a separate microwave-safe bowl, place the 1/3 cup of marshmallow fluff and microwave it for 20 seconds to make it loose and pourable.
- Swirl the Toppings: Using a large spoon, drop dollops of the melted fluff and the melted peanut butter onto the top of the brownie batter in an alternating, checkerboard pattern. Precision is not required here! Next, take a butter knife and make large, gentle swirls through the dollops. Do not over swirl the brownies you want distinct ribbons of peanut butter and marshmallow fluff, not a muddy mix.
- Bake and Cool: Place the pan in the oven to bake for 20 to 30 minutes. The brownies are done when the edges look set and a knife inserted into the middle comes out mostly clean, with maybe a few moist crumbs attached.
- Serve: Allow the brownies to cool completely before slicing. Once cooled, slice into 16 small brownies or 9 huge, indulgent brownies. Enjoy!
Pro Tip:
The cooling period is the most important step! If you try to slice these while they are warm, the marshmallow fluff will still be very gooey, making it hard to get clean cuts. Let them cool completely for the best, neatest squares.
Recipe Tips
- Parchment Paper is Essential: Lining the pan on all sides with parchment paper creates “slings” that allow you to lift the entire cooled batch out of the pan easily, which is crucial for cutting clean squares without damaging the gooey top.
- Don’t Overbake: Since the marshmallow fluff is already on top, watch the edges, not just the knife test. As soon as the edges are set and the knife is mostly clean, pull the brownies out to ensure they stay perfectly fudgy inside.
- Gentle Swirling: The goal of the swirl is contrast. Use wide, figure-eight motions with your knife rather than mixing vigorously. This ensures the distinct peanut butter and fluff layers remain separate.
- Uniform Batter: Ensure the boxed brownie batter is spread into a truly even layer before adding the toppings. This guarantees an even bake and consistent fudginess across the pan.
FAQs
Q: Can I use crunchy peanut butter? A: You can, but crunchy peanut butter won’t create the same smooth ribbons. The nuts will make the swirl look a bit chunkier, but the flavor will still be delicious.
Q: How do I store these brownies? A: Store cooled Fluffernutter Brownies in an airtight container at room temperature for up to 3 days.
Q: Why does the fluff need to be microwaved? A: Marshmallow fluff is thick straight from the jar. Microwaving it briefly makes it liquid enough to dollop and swirl easily without disturbing the underlying brownie batter.
Q: How do I get clean cuts? A: Make sure the brownies are completely cooled (this might take 2 hours or more). For extra-clean cuts, place the cooled brownies in the refrigerator for 30 minutes before cutting them with a large, sharp knife, wiping the blade clean between slices.
Serving Suggestions
These rich brownies are a satisfying dessert all on their own, but here are a few simple ways to serve them:
- Vanilla Ice Cream: Serve a warm brownie square a-la-mode with a scoop of vanilla ice cream for the ultimate hot-and-cold pairing.
- Milk or Coffee: A tall glass of cold milk or a hot cup of coffee is the perfect beverage pairing for this intensely rich dessert.
- Extra Peanut Butter Drizzle: Before serving, warm a small amount of extra peanut butter and drizzle it over the sliced brownies for an artistic finish.
Make This Recipe in Advance
The great thing about brownies is that they can be baked, cooled, and stored up to a day in advance, and they actually get fudgier overnight! We recommend baking them the day before you need them, allowing them to cool completely overnight, and slicing them the next morning for the cleanest cuts.
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Fluffernutter Brownies (Easy Boxed Mix)
- Total Time: 45 minutes
- Yield: 16 servings 1x
- Diet: Vegetarian
Description
Indulge in nostalgic comfort with these Fluffernutter Brownies! This easy, decadent dessert features a rich, fudgy chocolate base made from a boxed mix, elevated by beautiful, swirling ribbons of creamy peanut butter and sweet, sticky marshmallow fluff. It’s the perfect treat for peanut butter and chocolate lovers seeking a quick and addictive dessert.
Ingredients
Brownie Base
- 1 boxed brownie mix (9x9 inch size, plus ingredients required on the box)
Swirl Topping
- 1/3 cup creamy peanut butter
- 1/3 cup marshmallow fluff
Instructions
Step 1: Prepare the Pan and Batter
Preheat your oven to 350°F. Line a 9×9 inch baking pan with parchment paper, allowing the paper to overhang the edges to create “slings.” Prepare the brownie batter exactly according to the directions on the box. Pour the prepared batter into the parchment-lined pan and spread it into an even layer using a rubber spatula.
Step 2: Prepare the Swirls
Place the creamy peanut butter in a microwave-safe bowl and heat for 30 seconds until melted and easily pourable. In a separate microwave-safe bowl, place the marshmallow fluff and microwave for 20 seconds to make it loose and pliable.
Step 3: Swirl the Toppings
Using a large spoon, drop dollops of the melted peanut butter and the melted marshmallow fluff onto the top of the brownie batter in an alternating, random pattern. Take a butter knife and gently make large, figure-eight motions through the dollops to create distinct ribbons and swirls. Avoid over-swirling to prevent the flavors from mixing completely.
Step 4: Bake and Cool
Place the pan in the oven and bake for 20 to 30 minutes. The brownies are done when the edges look set and a knife inserted into the center comes out with only moist crumbs attached. Allow the brownies to cool completely before slicing (about 2 hours) for the neatest, cleanest cuts.
Step 5: Serve
Once fully cooled, lift the brownies out of the pan using the parchment paper slings and slice them into 9 or 16 squares.
Notes
Clean Cutting: For the absolute cleanest cuts, make sure the brownies are completely cooled (2 hours or more). For extra firmness, place the cooled brownies in the refrigerator for 30 minutes before cutting them with a large, sharp knife, wiping the blade clean between each slice.
Storage: Store cooled Fluffernutter Brownies in an airtight container at room temperature for up to 3 days. They tend to get even fudgier on the second day!
Flavor Boost: Before serving, warm a small amount of extra peanut butter and drizzle it over the sliced brownies, or serve a warm square a-la-mode with a scoop of vanilla ice cream.
- Prep Time: 15 minutes
- Cook Time: 30 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American
Nutrition
- Serving Size: 1/16th of recipe (estimated)
- Calories: 220
- Sugar: 25g
- Sodium: 140mg
- Fat: 11g
- Saturated Fat: 4g
- Unsaturated Fat: 6g
- Trans Fat: 0g
- Carbohydrates: 28g
- Fiber: 1g
- Protein: 3g
- Cholesterol: 15mg
Keywords: Fluffernutter brownies, peanut butter, marshmallow fluff, fudgy brownies, easy dessert, boxed mix recipe
