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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


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


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!


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


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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