Peanut Butter Fluff Bars Recipe – Easy Friday Night Dessert Ideas with Marshmallow Fluff

Looking for the ultimate Friday night treat that’s equal parts gooey, nostalgic, and downright irresistible? Say hello to Peanut Butter Fluff Bars—a delicious, melt-in-your-mouth mashup of everything that made your childhood awesome. Think chocolate chip cookie dough, peanut butter cups, and a glorious layer of creamy marshmallow fluff all baked together into one epic dessert bar. Yeah, it’s a thing. And yeah, it’s totally as good as it sounds.

If you grew up loving Fluffernutter sandwiches (PB + marshmallow fluff + white bread = pure 90s kid energy), then you’re going to flip over these Fluffernutter Cookie Bars. They’re basically the grown-up (but still totally fun) version of that sticky-sweet classic. Only better—because chocolate.

Why You Need These in Your Life

Let’s just call it what it is: these bars are dangerously addictive. The chocolate chip cookie dough base is thick and chewy, with just the right amount of sweetness. Then there’s the marshmallow fluff layer—it melts into the cookie base and gets all golden and gooey in the oven. And don’t even get me started on the peanut butter cups. Each bite is a perfect combo of salty, sweet, and melty.

They’re one of my favorite Friday night dessert ideas because they’re fast to throw together, crowd-pleasing, and basically gone the minute they hit the table. Perfect for game nights, sleepovers, or when you just need to treat yourself after a long week of pretending to be an adult.

What Makes These Bars So Special?

Glad you asked.

• Made from scratch cookie dough: Sure, you can use pre-made dough to save time (we’ve all been there), but making it from scratch means you can amp up the peanut butter. More PB = more flavor = happier people.

• Use regular peanut butter: As much as I love natural peanut butter on toast, this is not the time. Natural stuff tends to separate and lacks the consistency needed here. Go with the classic smooth stuff—JIF or Skippy all the way.

• Any pan will do: We’ve tested this in both a 9-inch square pan and an 8×11 rectangle. Both work just fine. If you're using the square, just give it a couple extra minutes in the oven since the layers will be a bit thicker.

• Leftovers? What leftovers? On the rare chance you do have a few squares left, store them in an airtight container at room temp for 2–3 days. They probably won’t last that long though—just sayin’.

Marshmallow Fluff: The Unsung Hero

People sleep on marshmallow fluff, but it’s a kitchen MVP. Seriously—if you’ve ever wondered how to use marshmallow fluff, this is your answer. It gives the bars that gooey, sticky pull-apart magic that you just can’t fake. Plus, there are tons of marshmallow fluff ideas out there (hello, s’mores dip!), but this one? Total winner.

In fact, this recipe fits right in with treats using marshmallows and other retro-style Little Debbie dessert ideas. Only instead of plastic wrapping, you get that homemade warmth and love baked into every bite.

Feeling wild? Add crushed Butterfinger Fluff or swirl some Nutella into the mix for an extra decadent twist. I mean, it’s dessert—we’re not here to hold back.

One Last Thing…

If you’re deep in your “Pinterest recipes using fluff” rabbit hole, stop scrolling. This is it. These Peanut Butter Fluff Bars are everything you want from marshmallow puff recipes and more. Sweet, sticky, crunchy, chewy—and most importantly, easy. No complicated steps, no fancy equipment, just layered perfection baked in under 30 minutes.

So what are you waiting for? Whip up a batch, grab a fork (or don’t), and make your Friday night a little fluffier.

Pro tip: Don’t bring these to a potluck unless you’re cool with never bringing home leftovers. You’ve been warned.

Peanut Butter Fluff Bars Recipe – Easy Friday Night Dessert Ideas with Marshmallow Fluff

Prep Time: 10 minutes   |   Bake Time: 20 minutes   |   Cooling Time: 1 hour   |   Total Time: 1 hour 30 minutes

Yield: About 16 bars   |   Calories: Approx. 262 per bar

Ingredients:

• ½ cup softened butter
• ⅓ cup creamy peanut butter
• 1 cup packed brown sugar
• 1 large egg
• 1 teaspoon vanilla extract
• 1¼ cups all-purpose flour
• 9 to 12 regular-size peanut butter cups (avoid fun-size)
• ⅔ cup chocolate chips
• 7 ounces marshmallow fluff or marshmallow creme

Directions:

1. Heat your oven to 350°F (175°C). Line an 8×11-inch baking pan with parchment paper, leaving some overhang on the edges—this will make it easy to lift the bars out later.
2. To prepare the cookie dough: In a large bowl, cream together the softened butter and brown sugar until the mixture is light and fluffy—this usually takes about 3 minutes using a mixer.
3. Add the egg, peanut butter, and vanilla extract to the bowl. Mix well until everything is fully combined.
4. Gradually stir in the flour until the dough comes together. Then fold in the chocolate chips evenly.
5. Press roughly two-thirds of this cookie dough firmly into the bottom of your prepared baking pan, creating a smooth, even layer.
6. Evenly spread the entire marshmallow fluff container over the dough layer.
7. Arrange the peanut butter cups side-by-side on top of the marshmallow layer, making sure they don’t overlap.
8. Carefully spread the remaining marshmallow fluff over the peanut butter cups, covering them completely.
9. Take the remaining cookie dough and gently press it over the marshmallow fluff layer to form the top crust.
10. Bake the bars in the preheated oven for about 25 minutes, or until the edges turn a lovely golden brown.
11. Once baked, take the pan out of the oven but leave it on the counter to cool for an hour. This resting time helps the bars firm up perfectly.
12. After cooling, use the parchment paper edges to lift the entire slab out of the pan. Transfer it onto a wire rack and let it cool completely before cutting into squares.

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