Fluffernutter Bars – Delicious peanut butter bars topped with marshmallow frosting. Perfect for an afternoon snack or a holiday treat.

Fluffernutter Bars

This easy, nostalgic recipe for Fluffernutter Bars comes from Allison Miller’s cookbook Untraditional Desserts: 100 Classic Treats with a Twist. It combines a tender peanut butter bar base with a light marshmallow frosting for a sweet, satisfying bar that’s simple to pull together. The cookbook contains many inventive ideas, and this recipe is a standout for anyone who loves the classic peanut butter and marshmallow combo.

I was drawn to these bars while flipping through the book because I’d recently enjoyed a marshmallow frosting on a hot chocolate cake and wanted to try the flavor paired with peanut butter. The result is an indulgent, nostalgic bar that’s great for casual gatherings, bake sales, or a simple dessert.

The recipe yields about 15 bars in a 9×13-inch pan, but you can halve it to make 9 bars in an 8×8-inch pan. If you reduce the batch, remember to halve the frosting ingredients as well. For toppings, chopped peanuts and mini marshmallows both work well — I used the tiny marshmallows that typically come in hot chocolate packets.

How to make fluffernutter bars

Step 1 – Make the peanut butter bars

Combine the ingredients for the peanut butter base, spread the batter into a greased 9×13-inch pan, and bake until golden. Let the bars cool completely before frosting.

Step 2 – Make the marshmallow frosting

Beat together softened butter and marshmallow fluff, then add powdered sugar until smooth. Spread the frosting over the fully cooled bars and top with chopped peanuts or extra marshmallows if desired.

Looking for more peanut butter recipes?

Chocolate Peanut Butter Donuts
No Bake Peanut Butter Pie
Peanut Butter Mug Cake

Yield: 15 bars

Fluffernutter Bars

Fluffernutter Bars – Delicious peanut butter bars topped with marshmallow frosting. A simple, crowd-pleasing dessert.

Prep Time
10 minutes

Cook Time
25 minutes

Total Time
35 minutes

Ingredients

Peanut Butter Bars

3/4 cup unsalted butter, melted
1 cup brown sugar
1/2 cup granulated sugar
2 eggs
2 teaspoons vanilla extract
3/4 cup creamy peanut butter
1/2 teaspoon salt
1 1/2 cup all-purpose flour

Marshmallow Frosting

1/2 cup unsalted butter, softened
7 ounces marshmallow fluff
2 cups powdered sugar
1/2 cup chopped peanuts

Instructions

Preheat the oven to 350 degrees. Grease a 9×13-inch pan with nonstick cooking spray and set aside.
In a large bowl, beat together the melted butter, brown sugar, and granulated sugar until blended. Add the eggs and vanilla, then mix in the peanut butter until combined.
Whisk the salt and flour together in a separate bowl, then gradually add to the wet mixture and mix until just combined.
Spread the batter into the prepared pan and bake 25 to 30 minutes, until golden and a toothpick inserted in the center comes out clean. Remove from the oven and let cool completely.
To make the frosting, beat together the softened butter and marshmallow fluff. Add powdered sugar a cup at a time until smooth.
Spread the frosting over the cooled bars and sprinkle with chopped peanuts or mini marshmallows.