You know that magical combo of peanut butter and marshmallow fluff from childhood? The one that made sandwiches feel like a dessert? My Fluffernutter Brownies take that nostalgic flavor and bake it into the richest, fudgiest brownies you’ll ever taste. I still remember sneaking spoonfuls of fluff straight from the jar as a kid—now I get to relive those memories with every gooey, peanut buttery bite of these bars.
These aren’t just any brownies. The base stays dense and chocolatey (thanks to melted chocolate chips right in the batter), while that sweet-salty peanut butter and pillowy marshmallow layer in the middle makes them unforgettable. Perfect for when you want that classic fluffernutter experience… but in dessert form that’ll have everyone begging for the recipe.
The Must-Have Ingredients for Fluffernutter Brownies
Okay, let’s talk ingredients—because the magic starts here! I’ve made these brownies dozens of times, and I swear by these exact measurements. Trust me, that peanut butter-to-fluff ratio? Perfection. Here’s what you’ll need:
- 1 ⅓ cups unsweetened cocoa powder – The deep chocolate flavor base (don’t skimp!)
- 1 cup all-purpose flour – Spoon and level it, no packing!
- 1 teaspoon baking powder + ½ teaspoon kosher salt – For just the right lift and balance
- 1 teaspoon espresso powder – My secret weapon to intensify the chocolate
- 2 sticks (1 cup) unsalted butter, room temp – Soft enough to leave a fingerprint indent
- 2 cups granulated sugar – We’re making fudgy, not cakey, brownies here
- 1 cup semi-sweet chocolate chips – Melty pockets of joy
- 1 tablespoon vanilla extract – The good stuff, please
- 4 large eggs, room temp – Cracks easier and blends smoother
- ¾ cup creamy peanut butter – Jif or Skippy work great
- 1 cup marshmallow fluff – That iconic white fluff from the jar
See those room temp notes? Crucial! Cold eggs make the batter seize up, and hard butter won’t cream properly. I leave mine out for 1-2 hours before baking—plan ahead for the best texture.
How to Make Fluffernutter Brownies
Alright, let’s get to the fun part—making these dreamy brownies! I’ll walk you through each step, just like I’m right there in the kitchen with you. Grab your favorite mixing bowl and let’s go!
Preparing the Batter
First things first: preheat that oven to 350°F and line your 9×13-inch baking dish with parchment paper—trust me, this saves so much hassle later. Now, in a big bowl, whisk together the cocoa powder, flour, baking powder, salt, and espresso powder. Set it aside while you work your magic with the butter and sugar.
Here’s where patience pays off: in a saucepan over medium heat, melt the butter and sugar together. Stir occasionally until it hits a low boil, then let it bubble for 2 more minutes (or until it reaches 230°F if you’re using a thermometer). Remove from heat and stir in the chocolate chips and vanilla. Don’t panic if it looks grainy—that’s normal! Let it cool for about 10 minutes. This is key—if it’s too hot when you add the eggs, you’ll end up with scrambled eggs in your brownies (yikes).
Once cooled, add the eggs one at a time, stirring well after each. Then, gently fold in the dry ingredients just until combined. The batter will be thick and glorious—don’t overmix, or your brownies will turn out tough instead of fudgy.
Layering the Fluffernutter Filling
Now for the star of the show! Spread half the brownie batter into your prepared pan. Next, drop spoonfuls of peanut butter over the batter—I like to warm it slightly in the microwave for 10 seconds to make spreading easier. Use a butter knife or offset spatula to smooth it into an even layer.
For the marshmallow fluff, a piping bag works best (just snip the tip), but no worries if you don’t have one! Spoon the fluff into a zip-top bag, snip a corner, and pipe it in zigzags over the peanut butter. Or, if you’re feeling rustic, just dollop and swirl it with a spoon. Top with the remaining brownie batter—don’t worry if it doesn’t cover every inch; it’ll spread as it bakes.
Baking and Cooling
Pop those beauties into the oven for 28–30 minutes. You’ll know they’re done when the edges are set but the center still has a slight jiggle (a toothpick should come out with a few moist crumbs). Resist the urge to overbake—they’ll firm up as they cool.
Here’s the hardest part: let them cool completely in the pan before slicing. I know, I know—the smell is torture! But cutting warm brownies leads to a sticky mess. For clean squares, chill them in the fridge for an hour first, then use a sharp knife wiped clean between cuts. Worth the wait, promise!
Why You’ll Love These Fluffernutter Brownies
Let me count the ways these brownies will steal your heart (and probably your willpower):
- That fudgy texture – We’re talking melt-in-your-mouth dense, with just the right chew from the marshmallow layer.
- Nostalgia in every bite – It’s like your favorite childhood sandwich grew up and put on a chocolate tuxedo.
- So easy to make – No fancy techniques, just one bowl and some serious peanut butter enthusiasm.
- Perfect for sharing – These disappear fast at parties (but no judgment if you “forget” to tell anyone they’re ready).
- Endless smiles – That first bite when the peanut butter hits the marshmallow? Pure joy.
Seriously, these might just become your new bake-sale secret weapon or midnight snack obsession.
Tips for Perfect Fluffernutter Brownies
After making these more times than I can count (okay, fine—I lost track after batch twelve), here are my hard-earned secrets for brownie success:
Room temp is non-negotiable – Cold eggs make the batter clumpy, and stiff butter won’t blend smoothly with the sugar. I leave everything out on the counter for at least an hour before baking—just like Grandma taught me!
Mix with a light hand – Once you add the flour, stir just until the streaks disappear. Overmixed batter = tough brownies instead of that dreamy fudgy texture we crave.
Swirl smarter, not harder – If your peanut butter layer resists spreading, zap it in the microwave for 10 seconds first. For the fluff, a sandwich bag with the corner snipped works just as well as a piping bag in a pinch.
Slice like a pro – Run your knife under hot water and wipe it clean between cuts—those layers will stay picture-perfect. And if you can bear it, chilling the pan for 30 minutes first makes cleaner slices.
The toothpick lie – Unlike regular brownies, these might test “underdone” because of the gooey marshmallow layer. Pull them at 28 minutes unless the center looks truly liquid.
Fluffernutter Brownies Variations
Want to mix things up? Here are some fun twists I’ve tried that keep these brownies exciting every time:
- Crunchy peanut butter – Swap the creamy PB for extra texture (you’ll get little crispy bits in every bite!)
- Chocolate swirl magic – Melt ¼ cup extra chocolate chips and drizzle over the marshmallow layer before adding the top brownie batter
- Nutty goodness – Sprinkle crushed peanuts or walnuts between the layers for added crunch
- Double fluff – Can’t get enough marshmallow? Add an extra ½ cup fluff and swirl it into the top batter
- Cinnamon kiss – Stir ½ teaspoon cinnamon into the dry ingredients for a warm spice note
The beauty of this recipe? It’s like your favorite jeans—perfect as-is, but easy to dress up however you’re feeling!
Storing and Reheating Fluffernutter Brownies
Okay, let’s talk about keeping these beauties fresh—because let’s be real, you might not finish them all in one sitting (or maybe you will, no judgment here!). For storage, I always use an airtight container at room temperature. They’ll stay perfectly gooey for about 3 days this way. Just separate layers with parchment paper so they don’t stick together.
Want to freeze some for later? These brownies are freezer champs! Wrap individual squares tightly in plastic wrap, then pop them in a freezer bag. They’ll keep for up to 3 months. When the craving hits, thaw overnight in the fridge or microwave a frozen square for 15-20 seconds—just enough to get that marshmallow layer soft again.
Pro tip: If you reheat them, do it gently! 10 seconds in the microwave is plenty to bring back that fresh-from-the-oven magic without turning the fluff into liquid sugar. Trust me, I learned that the hard way!
Fluffernutter Brownies Nutrition Facts
Here’s the scoop on what you’re biting into (because let’s be honest – we all pretend not to count calories when brownies are involved). Each generous square packs about 320 calories, with 18g of that glorious fat from all the butter and peanut butter goodness. You’re looking at 38g carbs (28g from sugar – hey, it’s dessert!), 3g fiber, and 6g protein to balance things out.
Small print: These numbers can wiggle a bit depending on your exact ingredients (like natural vs. regular peanut butter, or different chocolate brands). But let’s be real – when marshmallow fluff’s involved, we’re hardly here for the nutritional virtues!
Fluffernutter Brownies FAQs
Can I use natural peanut butter instead of regular?
You can, but heads up—it’ll change the texture! Natural peanut butter tends to be oilier and less sweet. If you go this route, stir it really well first and maybe add an extra tablespoon of sugar to the batter. The layer might spread a bit thinner too since it’s runnier.
How do I keep the marshmallow fluff from melting into the brownies?
The trick is piping it in thick ribbons (not dollops) and working quickly once it’s layered. Chilling your fluff for 10 minutes beforehand helps it hold its shape better during baking. And whatever you do—don’t skip the cooling step! Those layers need time to set up properly.
Can I make these without espresso powder?
Absolutely! The espresso just deepens the chocolate flavor—you won’t taste coffee. If you don’t have any, substitute 1 teaspoon instant coffee granules or leave it out entirely. They’ll still be delicious, just slightly less rich.
Why did my peanut butter layer sink?
This happens if the bottom brownie layer is too thin or the batter is too runny. Make sure to spread a good thick base (about ½ inch) and let the butter-sugar mixture cool properly before adding eggs. A thicker base = better support for those dreamy layers!
Can I double this recipe?
I’d recommend baking two separate batches instead of doubling. These brownies rely on precise baking times, and a thicker pan might leave you with undercooked centers or overdone edges. Plus—more brownies is never a bad thing, right?
Fluffernutter Brownies: Decadent Peanut Butter Marshmallow Bliss
- Total Time: 45 minutes
- Yield: 12 brownies 1x
- Diet: Vegetarian
Description
Rich and fudgy brownies layered with creamy peanut butter and marshmallow fluff for a delicious twist on classic brownies.
Ingredients
- 1 ⅓ cups (167.3 g) regular unsweetened cocoa powder
- 1 cup (125 g) all-purpose flour
- 1 teaspoon baking powder
- ½ teaspoon kosher salt
- 1 teaspoon espresso powder
- 1 cup (2 sticks / 227 g) unsalted butter, room temperature
- 2 cups (400 g) granulated sugar
- 1 cup (168 g) semi-sweet chocolate chips
- 1 tablespoon vanilla extract
- 4 large eggs, room temperature
- ¾ cup (193.5 g) creamy peanut butter
- 1 cup (96 g) marshmallow fluff
Instructions
- Preheat the oven to 350°F. Line a 9×13-inch ceramic baking dish with parchment paper.
- To a large bowl, add cocoa powder, flour, baking powder, salt, and espresso powder. Whisk to combine and set aside.
- In a large saucepan over medium heat, add butter and sugar. After the butter has melted, heat to a low boil and cook for 2 more minutes, or until it reaches 230°F on an instant-read thermometer, stirring occasionally.
- Remove from heat and stir in the chocolate chips and vanilla until completely melted. (The mixture might still be grainy.) Allow it to cool for about 10 minutes.
- Add eggs, one at a time, stirring constantly until smooth.
- Add the dry ingredients to the chocolate mixture and mix until just combined. The batter will be thick.
- Spread half of the batter into the lined baking dish.
- Spread the peanut butter over the batter. Then, using a piping bag or a plastic bag with the corner cut off, pipe the marshmallow fluff on top of the peanut butter.
- Top with the remaining brownie batter.
- Bake for 28-30 minutes.
- Allow the brownies to cool completely before cutting and serving.
Notes
- Use room temperature ingredients for best results.
- Do not overmix the batter to keep the brownies fudgy.
- Let the brownies cool completely before slicing for clean cuts.
- Prep Time: 15 minutes
- Cook Time: 30 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American
Nutrition
- Serving Size: 1 brownie
- Calories: 320
- Sugar: 28g
- Sodium: 120mg
- Fat: 18g
- Saturated Fat: 9g
- Unsaturated Fat: 7g
- Trans Fat: 0g
- Carbohydrates: 38g
- Fiber: 3g
- Protein: 6g
- Cholesterol: 70mg