Name: Easy Fluffernutter Bars Recipe
Prep time: 10 min
Cook time: 30 min
Total time: 40 min
Cuisine: American
Ingredients: ½ cup unsalted butter, melted (1 stick or 113g); ½ cup creamy peanut butter (120g); ½ cup packed dark or light brown sugar (100g); ⅓ cup granulated sugar (67g); 1 teaspoon baking powder; ½ teaspoon kosher salt; 1 large egg, room temperature preferred; 2 teaspoons pure vanilla extract; 1 cup all-purpose flour (125g); 2 cups mini marshmallows (96g); Optional: 1-2 tablespoons peanut butter for drizzling

Jump to Recipe· 4.2 from 11 reviews

I absolutely adore sharing this Easy Fluffernutter Bars Recipe with you because it combines two of my favorite things: peanut butter and marshmallow fluff, but in an easy, baked form that feels like a nostalgic hug in every bite. It’s one of those recipes that feels fancy yet is so simple to throw together in one bowl, making it my go-to when I want a sweet treat without the fuss. The gooey marshmallows on top with a perfectly tender peanut butter base are truly irresistible, and I’m excited for you to taste the magic.

Why You'll Love This Easy Fluffernutter Bars Recipe

What makes this recipe stand out for me is the balance of flavors and textures. The richness of the peanut butter melds beautifully with the light sweetness of the brown and granulated sugars, while the mini marshmallows add that soft, pillowy contrast you don’t get with ordinary bars. I love how the baking powder gives the bars just enough lift, so they’re neither dry nor dense but perfectly tender. Each bite is a delightful mix of creamy, chewy, and slightly crisp edges that keep me coming back for more.

I also can’t overstate how easy and fun this recipe is to make, especially because everything happens in one bowl. It doesn’t require any fancy equipment or complicated steps, which means you can whip it up on a busy afternoon or for a last-minute get-together. These bars are ideal for serving at family dinners, holiday parties, or just because you deserve a sweet treat at home. Their nostalgic, comforting nature always sparks smiles, and I truly believe these bars have a way of bringing people together.

Ingredients You'll Need

The image shows a white marbled background with nine small white and wooden bowls and one large egg arranged neatly. Starting from the top left, there is melted unsalted butter in a small saucepan with a silver handle. To the right, a white bowl holds a smooth, creamy light brown peanut butter. Below the butter, a small wooden bowl contains white kosher salt. In the center, a small clear glass bowl is filled with dark brown vanilla extract. Moving right, a white bowl holds a mix of light brown brown sugar and white granulated sugar. Below the salt, a grayish white bowl contains all-purpose flour with a powdery texture. Beneath the vanilla, a single large white egg is placed on the surface. Next to the egg at the bottom center, a small clear glass bowl with white baking soda powder is visible. Lastly, on the bottom right, a white bowl is filled with many small, puffy white mini marshmallows. Photo taken with an iphone --ar 4:5 --v 7

The ingredients for these bars are straightforward but play a vital role in creating that signature Fluffernutter flavor. Each one is simple, pantry-friendly, and contributes to the perfect combination of taste and texture — from the creamy peanut butter that forms the backbone, to the marshmallows that add that luscious gooey top.

Tip!

You’ll find all ingredient quantities in the recipe card below.

Unsalted butter (½ cup): Melting it first ensures a smooth blend with the peanut butter, adding richness without overpowering the flavor.
Creamy peanut butter (½ cup): I use a medium-roast, creamy style for that classic smooth texture and peanut flavor.
Brown sugar (½ cup): Adds warmth and subtle caramel notes that complement the peanut butter perfectly.
Granulated sugar (⅓ cup): Balances the sweetness and gives a slight crispness to the edges when baked.
Baking powder (1 teaspoon): Just the right amount to keep the bars light but still sturdy enough to hold their shape.
Kosher salt (½ teaspoon): Enhances all the sweet flavors and cuts through the richness.
Large egg (1): I always like to use room temperature eggs for better mixing and texture.
Pure vanilla extract (2 teaspoons): Adds depth and a lovely fragrant note that elevates the whole bar.
All-purpose flour (1 cup): The structure builder without making the bars too dense.
Mini marshmallows (2 cups): This is the magic touch that brings the gooey, fluffy layer I love so much in these bars.

Directions

Step 1: Preheat your oven to 350°F and prep an 8x8 inch baking pan by lining it with parchment paper or foil. I like to lightly butter the parchment or foil to make sure the bars come out easily, making sure to leave an overhang on the sides for simple lifting later.

Step 2: In a medium to large bowl, whisk together the melted butter and creamy peanut butter until silky smooth. Then add the brown sugar, granulated sugar, baking powder, and kosher salt; whisk everything until it’s fully combined and uniform in color.

Step 3: Crack in the egg and pour in the vanilla extract, then whisk again until everything is fully blended and glossy.

Step 4: Add the flour last, folding it into the wet ingredients gently with a spatula until just combined. The batter will be thick—this is exactly what you want!

Step 5: Spread about two-thirds of the batter evenly into the prepared pan and bake for 15 minutes. Meanwhile, pop the leftover dough into the fridge to chill while the first layer bakes.

Step 6: Once the initial layer has baked, carefully remove the pan from the oven (it will be hot, so use oven mitts!). Immediately spread the two cups of mini marshmallows evenly over this baked peanut butter base.

Step 7: Remove the chilled dough from the refrigerator and crumble it over the marshmallow layer. Return the pan to the oven and bake for another 12 to 15 minutes, or until the edges of the bars are golden and the marshmallows are melty and just starting to brown.

Step 8: Allow the bars to cool completely in the pan on a wire rack before cutting. If you want to take it up a notch, melt 1 to 2 tablespoons of peanut butter and drizzle it over the cooled bars for an extra touch of richness.

Step 9: Cut into your desired portions and enjoy these delightful, nostalgic bars!

Servings and Timing

This recipe makes about 16 servings, which is great for sharing with friends or family. The prep time is around 10 minutes, and baking takes about 27 to 30 minutes total, allowing for a 45-minute complete turnaround from start to finish. A cooling period is essential to let everything set properly before slicing, so I recommend at least 20 minutes resting time once out of the oven.

How to Serve This Easy Fluffernutter Bars Recipe

A square metal baking pan filled with a layered dessert, lined with parchment paper visible at the edges, sits on a surface that has a white marbled texture. The dish has two visible layers: the bottom layer is light brown with a smooth texture, while the top layer is generously covered with white melted marshmallows that bubble and spread unevenly across the surface, creating a soft, puffy texture with some golden brown spots peeking through. The pan edges frame the dessert tightly, showing the contrast between the soft top and the dense-looking base. Photo taken with an iphone --ar 4:5 --v 7

When it comes to serving these bars, I love to keep it simple but inviting. They are delicious at room temperature, making them perfect for casual snacking or as part of a dessert platter. I often cut them into smaller squares to serve at parties where guests can grab them easily without needing a fork or plate. If you want to dress them up a bit, a light dusting of powdered sugar or a drizzle of chocolate adds a lovely visual and flavor contrast.

These bars pair wonderfully with a glass of cold milk or even a creamy coffee or chai latte for a cozy afternoon treat. On warmer days, I sometimes chill the bars before serving for a firmer texture that’s refreshing and satisfying. For events like family dinners or holiday gatherings, they make a nostalgic yet unique dessert option that guests always ask for seconds of.

To plate, I recommend arranging the bars on a bright or patterned platter to make the warm golden hues of the bars pop visually. Because they are so rich, serving smaller portions feels just right, especially if you pair them with fresh fruit or light whipped cream. Trust me, presentation can turn these easy bars into a real centerpiece of your dessert table!

Variations

I love experimenting with this Easy Fluffernutter Bars Recipe to suit different tastes and dietary needs. For example, swapping out the all-purpose flour for gluten-free flour blends works beautifully here if you want a gluten-free treat. I’ve also tried vegan versions by replacing the egg with a flax egg and using dairy-free butter and peanut butter alternatives — the bars still turn out wonderfully chewy and packed with flavor.

Another fun twist is to mix in chopped peanuts or chocolate chips into the batter for added texture and bursts of flavor. You can switch up the nut butter too — almond or cashew butter gives a milder, slightly different taste while still maintaining the creamy base. For those who love extra gooeyness, adding a swirl of marshmallow fluff inside the batter before baking is a game changer.

If you want to experiment with cooking methods, I’ve even adapted these bars slightly to bake in a muffin tin for individual servings or used a broiler briefly at the end to get a golden toasted marshmallow top. Playing around with these variations keeps this recipe exciting and adaptable no matter the occasion.

Storage and Reheating

Storing Leftovers

I store leftover Fluffernutter bars in an airtight container at room temperature for up to 3 days to keep them soft and fresh. If your kitchen is warm, I recommend refrigeration to prevent the marshmallows from melting or getting sticky, but just bring them back to room temperature before serving for the best texture.

Freezing

These bars freeze really well! I wrap them tightly in plastic wrap and then place them in a freezer-safe container or bag. They’ll keep nicely in the freezer for up to 2 months. When I want to enjoy one, I just let it thaw at room temperature for about an hour or so — the flavors and textures hold up wonderfully.

Reheating

To warm leftovers, I prefer a quick microwave zap for about 10 to 15 seconds, which revives the gooey marshmallow softness perfectly. Avoid reheating in the oven for too long because the bars can dry out quickly. If you want to restore a bit of that fresh-baked softness, adding a small piece of bread to the container when storing helps retain moisture.

FAQs

Can I use natural peanut butter for this recipe?

Yes, you can use natural peanut butter, but keep in mind it is often thinner and separates. Make sure to stir it well before measuring, and be aware this might slightly affect the texture, making the bars a little less dense but still delicious.

What can I use as a substitute for marshmallows?

If you don’t have mini marshmallows, you can use marshmallow fluff spread evenly over the first baked layer before crumbling the remaining dough on top. Alternatively, chopped larger marshmallows can work, but keep an eye on them while baking to avoid excessive browning.

Are these bars gluten-free?

The traditional recipe is not gluten-free due to the all-purpose flour, but you can easily substitute with a gluten-free flour blend. Just make sure it contains xanthan gum or a similar binder to keep the bars from crumbling.

Why do I need to refrigerate the second portion of dough?

Refrigerating the leftover dough firms it up, making it easier to crumble gently over the marshmallow layer. This layer of crumbled dough creates a delightful textured topping that bakes separately and prevents it from sinking into the marshmallows.

Can I make these bars ahead of time?

Absolutely! These bars are great made a day in advance. Just store them covered at room temperature or in the fridge, and they’ll taste just as fantastic — if not better — the next day as the flavors develop.

Conclusion

I truly hope you’ll give this Easy Fluffernutter Bars Recipe a try soon. It’s one of those simple, sweet treats that feels like a nostalgic celebration in every bite, yet easy enough to whip up anytime you’re craving something cozy and comforting. From the soft peanut butter crumb to the gooey marshmallow topping, these bars never fail to brighten my day, and I know they’ll do the same for you.