Oh my gosh, you HAVE to try these Fluffernutter Brownies! Picture this – fudgy chocolate brownies hugging a gooey layer of peanut butter and marshmallow fluff. It’s like your favorite childhood sandwich got a serious upgrade. I first made these for a bake sale years ago, and let me tell you, people went nuts (pun totally intended). The way the sweet marshmallow and rich peanut butter swirl together with that deep chocolate flavor? Absolute magic. My kids beg me to make these every weekend, and honestly, I don’t fight them too hard on it – they’re that good!

Why You’ll Love These Fluffernutter Brownies

Trust me, these aren’t just any brownies – they’re pure happiness in a baking dish! Here’s why they’ll become your new obsession:

That perfect texture: Fudgy centers with slightly crisp edges that make you close your eyes and sigh
Easy-peasy: No fancy techniques – just simple layers of deliciousness
The flavor balance: Sweet marshmallow dances with salty peanut butter like they were made for each other
Crowd-pleaser magic: Kids go wild for them, adults sneak seconds… everybody wins!

Seriously, one bite and you’ll understand why I make these at least twice a month!

Ingredients for Fluffernutter Brownies

Gather these goodies – exact measurements matter here for that perfect fudgy texture:

1 ⅓ cups (167.3 g) unsweetened cocoa powder – sifted if it’s lumpy
1 cup (125 g) all-purpose flour – spoon and level it, don’t scoop!
1 teaspoon baking powder – make sure it’s fresh
½ teaspoon kosher salt – balances all that sweetness
1 teaspoon espresso powder – my secret flavor booster
1 cup (2 sticks / 227 g) unsalted butter – room temp is crucial
2 cups (400 g) granulated sugar
1 cup (168 g) semi-sweet chocolate chips
1 tablespoon vanilla extract – yes, a full tablespoon!
4 large eggs – also room temp, please
¾ cup (193.5 g) creamy peanut butter – the regular kind, not natural
1 cup (96 g) marshmallow fluff – straight from the jar works great

Ingredient Notes & Substitutions

That espresso powder? It’s not for caffeine – it makes the chocolate taste richer without any coffee flavor. If you’re out, you can skip it. For peanut butter, stick to creamy conventional brands (the oil-separating natural kinds make the layers weird). Almond butter works in a pinch, but skip the crunchy varieties – we want smooth layers. And about that marshmallow fluff? Homemade is great, but the jarred stuff gives perfect consistency every time. Trust me, I’ve tested both ways!

Equipment You’ll Need

Okay, let’s talk tools! You probably have most of these already, but just in case – here’s what you’ll grab:

9×13-inch ceramic baking dish – metal works too, but ceramic gives the best edges
Parchment paper – lifesaver for easy brownie removal
Medium saucepan – for that butter-sugar mixture
Mixing bowls – one big, one medium
Piping bag or zip-top bag (optional) – makes spreading marshmallow fluff way less messy!

That’s it! No fancy gadgets required – just good old-fashioned baking basics.

How to Make Fluffernutter Brownies

Alright, let’s get to the fun part! Here’s exactly how I make these dreamy brownies every time:

Preheat that oven! Get it to 350°F (175°C) and line your baking dish with parchment paper – trust me, you’ll thank me later when these beauties slide right out.
Whisk dry ingredients in your big bowl – cocoa powder, flour, baking powder, salt, and that magical espresso powder. Set it aside while you work on the good stuff.
Melt butter and sugar in your saucepan over medium heat, stirring occasionally until it hits 230°F (110°C). I use an instant-read thermometer – it should look glossy and smell like caramel. This step gives our brownies that perfect fudgy texture!
Off the heat, stir in chocolate chips and vanilla until everything’s smooth and dreamy. Let it cool for about 10 minutes – patience is key here so we don’t scramble our eggs!
Beat in eggs one at a time, stirring like crazy after each one. The mixture will go from shiny to thick and glorious.
Fold in dry ingredients gently – just until no flour streaks remain. Overmixing makes tough brownies, and we want fudgy perfection!
Layer it up! Spread half the batter in your dish, then dollop peanut butter evenly over the top. For the marshmallow fluff, I put it in a piping bag (or zip-top bag with the corner snipped) and pipe little swirls across the peanut butter – makes it way easier to spread the top layer without making a mess!
Bake 28-30 minutes until the edges look set but the center still has a slight jiggle. They’ll keep cooking as they cool – promise!
Cool completely before cutting. I know, the wait is torture, but rushing this means gooey instead of clean slices. Worth it!

Tips for Perfect Fluffernutter Brownies

Few quick pro tips from my many (many!) batches: Don’t overmix the batter – a few flour streaks are okay! When layering, keep peanut butter and marshmallow about ½ inch from the edges so they don’t burn. And that cooling time? Non-negotiable – warm brownies turn into a delicious mess (still tasty, just not pretty)!

Serving and Storing Fluffernutter Brownies

Oh, the joy of eating these brownies warm with a scoop of vanilla ice cream melting over the top – absolute heaven! They’re fantastic at room temperature too, but if you want that gooey marshmallow experience, just pop a square in the microwave for 10 seconds. Store leftovers (ha! as if you’ll have any) in an airtight container for up to 3 days. They freeze beautifully too – just layer them between parchment paper in a container and they’ll keep for a month. Thaw at room temperature or give ’em a quick microwave zap before serving.

Fluffernutter Brownies Nutrition Info

Now, let’s be real – we’re not eating brownies for their health benefits! But because I know some of you (like me) like to track these things, here’s the approximate nutrition per brownie: 320 calories, 18g fat (9g saturated), 38g carbs (3g fiber, 28g sugar), and 6g protein. Remember, these are estimates – actual values can vary based on ingredient brands and how big you cut those squares (no judgment if yours are extra generous!).

Fluffernutter Brownies FAQs

I get asked these questions all the time about my Fluffernutter Brownies – here’s what you need to know!

Can I use homemade marshmallow fluff?
Absolutely! Just make sure it’s the same consistency as the jarred kind – too runny and it’ll soak into the layers. I’ve found homemade needs to be slightly stiffer than you’d normally make it for these brownies.

Why did my brownies sink in the middle?
This usually means either the butter-sugar mixture wasn’t hot enough (that 230°F is crucial!) or the oven temperature was off. An oven thermometer helps – these brownies need steady, even heat.

Can I freeze the unbaked batter?
I don’t recommend it – the layers get weird when thawed. But baked brownies freeze perfectly! Just wrap them well to prevent freezer burn.

Help! My marshmallow layer disappeared!
This happens if you overmix the top batter layer – gently spread it to preserve those fluffy pockets. A piping bag helps keep the marshmallow distinct too.

Share Your Fluffernutter Brownies

Did you make these brownies? I’d love to see your creations! Snap a pic, tag me on Pinterest, or leave a comment below with your twists – maybe you added crushed pretzels or drizzled caramel? Happy baking, friends!

For other sweet treats, check out our desserts & sweets category for more recipes you’ll love.

Fluffernutter Brownies – The Crave-Worthy Peanut Butter Marshmallow Treat

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Author: Chef Ivan
Total Time: 45 minutes
Yield: 12 large brownies 1x
Diet: Vegetarian

Print Recipe

Description

Rich and fudgy brownies with layers of creamy peanut butter and marshmallow fluff.

Ingredients

Scale

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

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Instructions

Preheat your oven to 350°F (175°C). Line a 9×13-inch ceramic baking dish with parchment paper.
In a large mixing bowl, whisk together cocoa powder, flour, baking powder, kosher salt, and espresso powder.
Melt butter and sugar in a saucepan over medium heat, stirring occasionally until it reaches 230°F (110°C).
Remove from heat and stir in chocolate chips and vanilla extract until smooth. Let cool for 10 minutes.
Beat in the eggs one at a time, stirring constantly after each addition.
Fold the dry ingredients into the chocolate mixture until just combined.
Spread half the batter into the baking dish. Layer with peanut butter, then marshmallow fluff.
Top with the remaining batter and bake for 28-30 minutes until edges are set.
Cool completely before cutting into squares.

Notes

For a smoother texture, sift the dry ingredients.
Use a piping bag for even marshmallow distribution.
Store in an airtight container for up to 3 days.

Prep Time: 15 minutes
Cook Time: 28-30 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: 65mg