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Fluffernutter Bars

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5 from 1 vote

Perfectly chewy peanut butter blondies are topped with sky-high, homemade marshmallow fluff! Next time try my fan favorite fluffernutter cookies or fluffernutter rice krispie treats.

Fluffernutter bars: peanut butter blondies topped with homemade marshmallow fluff

These fluffernutter bars were born from a craving for peanut butter and fluff. I would have just made a sandwich, but I was stuck at home during one of our bagillion nor’easters this year and we ran out.

I KNOW. Cardinal rule of an upcoming storm: cause a stampede at the grocery store and buy all the milk and bread, even if you don’t eat bread or need milk. Me? I stock up on wine and chocolate. Priorities.

Peanut butter blondie bars

So then I was going to make my fan favorite fluffernutter cookies, but I wanted more fluff. I finally decided that I would try my hand at peanut butter bars and go from there.

Thankfully, that experiment went pretty damn well because the bars came out exactly the way I wanted them to! Soft, but not cakey. Chewy, but not overly dense. And most importantly, full of peanut buttery flavor.

I have this habit of cutting off the edges of brownies and bars while they’re cooling, and I do it for two reasons: to taste test and to even out the bars themselves. You know how you end up with curved corner pieces and something the edges will be raised on the perimeter?

Yeah, I just cut those off and eat them. Everything is evened out and I get a snack. Win win.

Peanut butter blondie bars

While the bars cooled, I did some online searching for marshmallow frostings. I didn’t have any jars of Fluff on hand (which is actually kind of shocking), so I needed to make my own.

My plan was to reuse the recipe for my s’mores cupcakes which is perfectly delicious, but I didn’t have enough granulated since the bars themselves used up what I had around the house.

Guys… being stuck inside during nor’easters is the worst.

Rather than trying to reinvent the wheel and potentially wasting ingredients on failed batches, I went with this marshmallow recipe from Deliciously Organic.

It’s even paleo if you want to use it for other recipes that you want to be 100% paleo! Because this recipe? This is most definitely not paleo.

We’re using butter and sugars and peanut butter, which on its own isn’t paleo because peanuts aren’t nuts, they’re legumes – and those are off limits for a paleo diet.

Did you know that? I didn’t, until I really got into paleo baking and cooking. If you didn’t know that either, consider this your fun fact of the day! You’re welcome. 

Homemade marshmallow fluff

Okay, so about that marshmallow frosting… it’s perfect for this.

It’s stiff enough that you can layer it sky high on top of the peanut butter bars, which is of course what I did.

Fluffernutter bars: peanut butter blondies topped with homemade marshmallow fluff

If you want a thinner layer, that’s fine, too… I suppose. You could make two batches of bars to frost with it, or you can store it in an airtight container in the fridge.

When you want to use it again, just whip it back into shape (it will separate as it settles).

Fluffernutter bars: peanut butter blondies topped with homemade marshmallow fluff

The combination of this frosting and these bars are fluffernutter perfection. I love it so much. 

The bars can easily stand on their own though – so if you wanted to leave them naked, you’ll be just fine. Or you could top them with something else – maybe my mascarpone whipped cream, or cookie butter frosting, or just a hearty drizzle of dark chocolate. You really can’t go wrong.

Still not enough fluffernutter fun for you? Try these fluffernutter cupcakes from my girl Lauren. You won’t regret it, I promise.

Fluffernutter bars: peanut butter blondies topped with homemade marshmallow fluff

After you’ve made this recipe, please consider coming back to share your experience with others by leaving a comment below with a star rating!

Fluffernutter bars: peanut butter blondies topped with homemade marshmallow fluff

Fluffernutter Bars

5 from 1 vote
Perfectly chewy peanut butter blondies are topped with sky-high, homemade marshmallow fluff!
Prep Time 15 minutes
Cook Time 30 minutes
Total Time 45 minutes
Servings 24 bars

Ingredients
  

Peanut butter bar layer

  • cup unsalted butter, very soft
  • ¾ cup brown sugar, packed
  • ½ cup granulated sugar
  • ½ cup creamy peanut butter
  • 2 eggs, room temperature
  • 1 teaspoon vanilla
  • 1 cup flour
  • 1 teaspoon baking powder
  • ½ teaspoon salt

Fluff layer

  • 1 ¼ cups maple syrup
  • teaspoon salt
  • 2 large egg whites
  • ¼ teaspoon cream of tartar
  • 2 teaspoons vanilla extract

Instructions
 

Peanut butter bar layer

  • Preheat the oven to 350°F and line a 9x13 inch pan with parchment paper. Set aside.
  • In a large bowl, use a hand mixer to beat together butter, brown sugar and granulated sugar together until combined.
  • Add in the peanut butter, eggs, and vanilla and beat to combine.
  • Use a spatula to fold in the flour, baking powder, and salt.
  • Spread evenly into prepared pan and bake for 28-30 minutes, or until a toothpick inserted into the center comes out with a moist crumb.
  • Let cook in pan for 5 minutes and then lift out and let cool completely on a wire rack.

Fluff layer

  • Place the egg whites and cream of tartar in the bowl of a stand mixer fitted with a whisk attachment and whip the egg whites to soft peaks on medium speed.
  • At the same time, place maple syrup and salt in a medium sauce pan and bring to a boil over high heat. Continue boiling until the mixture reaches 240°F on a thermometer.
  • When the syrup reaches 240°F, reduce the mixer speed to low and slowly add maple syrup. Increase the speed to medium-high and whip for about 7 minutes - the marshmallow crème is stiff and glossy.
  • Add the vanilla and whip an additional 2 minutes.
  • Frost cooled peanut butter bars, cut into 24 bars and enjoy!

Notes

Cover and store leftover bars at room temperature for up to a week.

Nutrition

Calories: 169kcal | Carbohydrates: 27g | Protein: 3g | Fat: 6g | Saturated Fat: 2g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 2g | Trans Fat: 1g | Cholesterol: 20mg | Sodium: 116mg | Potassium: 103mg | Fiber: 1g | Sugar: 21g | Vitamin A: 99IU | Calcium: 40mg | Iron: 1mg
Course Dessert
Cuisine American
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