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    Home » Recipes » Brownies & Bars

    Fluffernutter Bars

    Published: Mar 11, 2018 · Last modified: Apr 24, 2022 by Leslie Kiszka / This post may contain affiliate links.

    Jump to Recipe Pin Recipe
    5 from 2 votes
    Fluffernutter Bars | Stress Baking
    Fluffernutter Bars | Stress Baking
    Fluffernutter Bars | Stress Baking

    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 2 votes
    Perfectly chewy peanut butter blondies are topped with sky-high, homemade marshmallow fluff!
    Print Recipe Pin Recipe
    Prep Time 15 minutes
    Cook Time 30 minutes
    Total Time 45 minutes
    Servings 24 bars
        ✓ Read the recipe from beginning to end
          ✓ Check oven calibration
            ✓ Check expiration dates
              ✓ Properly measure ingredients
                ✓ Check butter temperature

    Recommended Equipment

    • 9″x13″ baking dish
    • Parchment paper
    • Mixing bowls
    • Hand mixer
    • Spatula
    • Stand Mixer
    • Medium saucepan
    • Thermometer (ChefAlarm)

    Ingredients
     
     

    Peanut butter bar layer

    • ⅓ 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
    • ⅛ 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 9×13 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.
      ⅓ cup unsalted butter | ¾ cup brown sugar | ½ cup granulated sugar
    • Add in the peanut butter, eggs, and vanilla and beat to combine.
      ½ cup creamy peanut butter | 2 eggs | 1 teaspoon vanilla
    • Use a spatula to fold in the flour, baking powder, and salt.
      1 cup flour | 1 teaspoon baking powder | ½ teaspoon 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.
      2 large egg whites | ¼ teaspoon cream of tartar
    • 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.
      1 ¼ cups maple syrup | ⅛ teaspoon salt
    • When the syrup reaches 240°F, reduce the mixer speed to low and slowly add vanilla. Increase the speed to medium-high and whip for about 7 minutes – the marshmallow crème is stiff and glossy.
      2 teaspoons vanilla extract
    • 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
    Author Leslie Kiszka
    Tried this recipe?Leave a comment and rating!

    Related Posts

    • Fluffernutter Rice Krispie Treats
    • Fluffernutter Cookies (Peanut Butter and Fluff)
    • Chocolate Chunk Peanut Butter Cookies
    • Paleo Chocolate Chip Cookies
    • Peanut Butter Cookie Dog Treats

    More Brownies & Bars

    • Easy Scotcheroos Recipe
    • Pumpkin Spice Rice Krispie Treats (Halloween Rice Krispie Treats)
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    Leslie Kiszka in a red dress

    About Leslie

    I'm the hot mess behind every recipe you see here! I use baking as an outlet for relieving stress and anxiety to provide you with approachable homemade recipes and a little humor, for good measure.

    learn more about Leslie →

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      Recipe Rating




    1. Debbye

      March 18, 2018 at 12:31 pm

      These look so moist, I just want to reach in and grab one. Love the whipped cream on top, too!

      Reply
      • Leslie Haasch

        March 18, 2018 at 4:23 pm

        It’s actually marshmallow fluff, but it’s delicious either way!

        Reply
    2. Amanda Mason

      March 18, 2018 at 11:20 am

      These look amazing! I hear you on the wine and chocolate…that’s me too! I dont eat bread or drink milk so I dont get that concept when a storm is coming like everyone else does lol! These do look like they turned out perfect! Right up my alley, for sure!

      Reply
    3. Sharon

      March 18, 2018 at 1:03 am

      We all need ‘more fluff’ in our life LOL and these bars sure deliver that. The delicious peanut butter later and frosting, so good.

      Reply
    4. prasanna hede

      March 17, 2018 at 2:14 pm

      These look superbly delicious and I am the only one at home who eats those edges! The fluffy layer is so interesting and yummy!

      Reply
    5. BettyDavies

      March 16, 2018 at 12:14 pm

      These look so delicious! They certainly wouldn’t last long in my house! I’m all for nibbling the edges too!

      Reply
    6. Analida's Ethnic Spoon

      March 15, 2018 at 9:28 pm

      Those blondies look lovely! I am too one who gets snowed in and have to cook all day when the “lake effect” storm hits us here. Baking is a nice way to spend the day. Thanks for sharing a great recipe!

      Reply
    7. Veena Azmanov

      March 15, 2018 at 6:18 pm

      Yup.. the edges are always my treat too! I’m nibbling on those because I earned it..!! Love the sounds of these bars. And I love the name too! Sounds so yum.

      Reply
    8. gritsandpineconescom

      March 14, 2018 at 11:31 am

      Wow! These look and sound absolutely delicious!!

      Reply
    9. Laineey

      March 14, 2018 at 10:02 am

      I love, love, love, love fluffernutters! If I had my druthers growing up, I would have had them every darned day for lunch, but my mother had other plans. Your fluffernutter bars looks so incredibly delicious especially with that delightful frosting! I want and need it so I’ll be making it. And yesterday’s nor’easter really made me extra hungry with all that shoveling so I won’t feel guilty cutting off the edges and eating them.

      Reply
    10. Patti @ Patty Cake's Pantry

      March 14, 2018 at 1:40 am

      I am in love with this recipe. I love fluffer butter sandwiches. I think it’s genius to trim the uneven edges to make it smoother. I’m going to have to start doing this for all of my blondies and brownies in the future purely for aesthetic reasons. It’s not because I want to eat the edges I trim away.

      Reply
    11. Kiki Johnson

      March 13, 2018 at 1:26 pm

      These looks AMAZING with all that fluff! I love how you described the texture of them. I can almost taste them. It certainly sounds like a peanut butter-lover’s dream come true.

      Reply
    12. Kate

      March 13, 2018 at 9:11 am

      These look sooooo good! I also just love to say fluffernutter. What a fun word! I think I first heard about fluffernutters on a podcast awhile ago. Love this dessert version!

      Reply
    13. Patti @ Patty Cake's Pantry

      March 13, 2018 at 2:27 am

      I like the way you think. Why didn’t I ever consider eating the uneven edges off of my brownies, or other bars, before frosting. I mean, it’s totally for the aesthetics, right? These look amazing. I love fluffer butter, so I pinned these and plan to make them soon.

      Reply
    14. Gloria Duggan

      March 12, 2018 at 10:01 pm

      Well I know for sure these would not last long in this house. They look like FUN to make…and more fun to eat. Who doesn’t love “fluffernutter”….. kids and adults go crazy for this.

      Reply
    15. Big Flavors from a Tiny Kitchen

      March 12, 2018 at 3:29 pm

      OK first of all I love the idea that you’ve justified trimming and eating the best part of brownies/blondies. I love the edges! And secondly – these look AMAZING! Love that you’ve used blondies as a base, and that topping looks absolutely luscious!

      Reply
      • Leslie Haasch

        March 12, 2018 at 4:13 pm

        Thank you! I’m glad to find another edge-lover!

        Reply

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