Rich and moist peanut butter cake topped with marshmallow frosting and peanut butter cups. It’s like biting into a fluffernutter sandwich, but better!
What is a Fluffernutter, you ask?
A fluffernutter is a peanut butter + marshmallow creme sandwich. My older sister Sarah loved them when we were growing up! The term fluffernutter can also describe desserts combining the tastes of peanut butter and marshmallow. And did you know? The Fluffernutter is the official sandwich of Massachusetts. They sure know what they’re doing up there!
I had leftover Fluff (marshmallow creme) from making my S’mores Cookie Bars (must make!). I brainstormed for a minute and decided to use the rest of the XXL jar for frosting. A quick marshmallow frosting to pair with a super-moist, dangerously good peanut butter cake.
The peanut butter cake is the same batter I use for my super-moist, super peanut buttery Peanut Butter Cupcakes. This is my go-to peanut butter cupcake. It’s not made with white sugar – all brown sugar, baby. The brown sugar and the eggs are why it is so darn moist!
I find that many peanut butter cupcakes and peanut butter cake recipes lack flavor. They tend to have a dry texture and not nearly enough peanut butter taste. My peanut butter cake and cupcake recipe is the complete opposite. It’s like biting into pure peanut butter.
The best part? The peanut butter cake is so easy to make!
Doesn’t the frosting look like a cloud? So good. Creamy marshmallow sitting atop a moist peanut butter cake. Fluffernutter at its finest.
I spread the frosting on the cake with a knife. Nothing fancy. I opted out of frosting the sides of the cake because it is SO much easier to just frost the top. Save yourself the time. Depending on how thick you slather the frosting onto the cake, you may have leftovers.
Leftover frosting is a wonderful accompaniment to graham crackers. Just sayin’.
Reese’s Peanut Butter Cups are the decor of choice for the cake. Because… why not? Chop up 8 full size Reese’s Cups and sprinkle around the edges. Or all over – whatever you prefer. Decorating the cake is almost as fun as eating it. (Almost.)
Like banana bread and carrot cake, I find that peanut butter cake tastes best on day 2 after the flavors have settled and have gotten friendly with one another. It is also more moist on the 2nd day as well. This didn’t stop us from digging right in after the photoshoot though!
It’s a one layer cake, which is much more practical for Kevin and I. A couple leftover slices can easily be given away to friends and neighbors. Double layer cakes and sheet cakes are my answer to birthdays and parties, but a simple cake like this can be made for any occasion. If you’d like to make this a double layer cake, simply double all of the ingredients and bake in two 9-inch round pans.
So there you have it… a twist on the classic Fluffernutter sandwich we remember as kids. It’s simply the best peanut butter cake I’ve ever eaten. I was blown away by its flavor and just how easy it was to make. There is no excuse not to try this if you’re a Fluffernutter Lover. 😉
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Rich and moist peanut butter cake topped with marshmallow frosting and peanut butter cups. It's like biting into a fluffernutter sandwich, but better!
Yield: 1 cake, serves 10
- 1/2 cup (1 stick or 115g) unsalted butter, softened to room temperature
- 3/4 cup (150g) packed dark brown sugar
- 2 large eggs
- 2/3 cup (170g) creamy peanut butter
- 1 teaspoon vanilla extract
- 1 and 1/4 cups (160g) all-purpose flour (careful not to overmeasure)
- 1 teaspoon baking powder
- 1/4 teaspoon salt
- 1/4 cup buttermilk*
- 7.5 oz (1 cup; 213g) container marshmallow creme (Fluff)
- 8 oz (225g) cream cheese, softened to room temperature*
- 1/2 cup (60g) confectioners' sugar
- 2 teaspoons vanilla extract
- 1/2 teaspoon salt
- 8 Reese's Peanut Butter Cups, chopped (optional)
- Preheat oven to 350F degrees. Spray a 9x2 inch cake pan (or 9-inch springform pan) with nonstick spray. Set aside.
- Make the cake: Using a handheld or stand mixer, beat the butter and brown sugar together on medium speed in a large bowl until creamed. About 2-3 minutes. Add eggs, one at a time, and beat until combined. Scrape down the sides of the bowl as needed. Add the peanut butter and vanilla extract, beating for about 2 full minutes. Set aside.
- In a medium sized bowl, toss together the flour, baking powder, and salt. Slowly add the dry ingredients to the wet ingredients in 3 additions, stirring by hand after each addition. Batter will be thick. Add the buttermilk and mix until just combined, do not overmix.
- Spoon the batter into the prepared cake pan. Bake for 20 minutes. Remove from the oven and loosely cover with aluminum foil. Bake for an additional 12-13 minutes or until a toothpick inserted in the center comes out clean. Allow cake to cool completely in the pan on a wire rack.
- Make the frosting*: In a medium sized bowl, beat the cream cheese on medium-high speed until smooth and creamy. Turn off the mixer, add the marshmallow creme and beat on low speed for 1 minute. Slowly add the powdered sugar and vanilla extract and beat for 1 minute. Add the salt and continue to beat. Add more powdered sugar if you'd like the frosting to be thicker. Add more salt to cut that extra sweetness.
- Remove the cake from the pan by inverting it onto a large plate or cake stand. Frost the cake as desired. There will be leftover frosting depending how much frosting you use. Decorate with chopped Reese's Cups. Cake stays fresh (covered) at room temperature or in the refrigerator for 4 days. Frost immediately before serving.
*Please use buttermilk to obtain the moistest texture.
*If you'd like to make this a double layer cake, simply double all of the ingredients and bake in two 9-inch round pans.
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If you love marshmallow, you have to try my S’mores Cookie Bars.
It’s like bringing the campfire inside. 😉
Today’s cake recipe is the same batter that I use for my Peanut Butter Cupcakes with Dark Chocolate Frosting.
So, have you ever had a fluffernutter sandwich?