These Fluffernutter Bars are peanut butter bars swirled with marshmallow cream to create some delicious, one-bowl bars you’ll want to share with everyone!
I’ve shown a ton of love for peanut butter on this site, but it’s usually paired with chocolate. Dark, milk or white, it’s seen ’em all. However, I sort of abandon all the other amazing ingredients peanut butter can be paired with, because let’s be real: rarely does anything beat chocolate.
I decided to branch out in the middle of trying this peanut butter bar/blondie-ish type recipe, and grabbed a jar of marshmallow fluff instead of chocolate chips for a change. The results: amazing.
Fluffernutter sandwiches are highly forgotten about after 4th grade when it becomes no longer acceptable to have marshmallows for lunch, but it’s such a good combo and so perfect for desserts. I love how these bars look too! The swirl of white in the bars is so pretty, and it don’t taste too bad either! ;)
The peanut butter base is like a chewy, soft peanut butter cookie. It’s so delicious! The swirl of marshmallow fluff adds some sweetness and extra gooey-ness, which I always appreciate. This doesn’t make a huge batch, which is nice because the bars are pretty sweet (from the marshmallow fluff) and pretty rich (from the peanut butter) so a little square goes a long way. Best of all, these babies only require one bowl, making them easy to get into the oven in 5 minutes flat, dirtying very few dishes along the way. My kind of recipe!
Hope you enjoy this fun twist on the childhood classic sandwich! :)

Fluffernutter Bars
Ingredients
- 1/4 cup butter, melted
- 1/2 cup peanut butter
- 1 egg
- 3/4 cup dark brown sugar
- 1/4 cup white sugar
- 1 teaspoon vanilla
- 3/4 cup flour
- 1/2 cup marshmallow fluff
Instructions
- Preheat oven to 350F. Line an 8-by-8-inch pan with aluminum foil and spray with cooking spray; set aside.
- In a medium-sized microwave-safe bowl, melt the butter, 45 seconds to 1 minute. Cool the butter for about 5 minutes, and then add the egg, peanut butter, sugars, and vanilla. Whisk together thoroughly. Add the flour and stir until just combined, taking care not to over-mix or the bars will be tough. Fold in tablespoon sized dollops of marshmallow cream, don't overmix or the fluff will disappear into the batter. You just want some streaks and some small dollops of fluff.
- Spread batter into prepared pan, smoothing it lightly with a spatula or offset knife. Bake for about 15 to 20 minutes, or until center is just set. A toothpick should come out mostly clean. Don't overbake; these are meant to be gooey and firm up as they cool. Let cool completely, slice, and serve!



Oh yumm! I recently made peanut butter s’mores, seriously delicious combo!
I totally agree! You need to try a s’mores with a Reese’s instead of a Hershey’s bar if you never have. It’s heaven!!
Oh heck yes. Great idea for some gooey and delicious bars!
These look delicious!
Definitely one of my fave combos! Cannot go wrong with PB & Fluff!
What happened to the peanut butter? When you say melt the butter did you also mean the peanut butter?
Whoops, thanks for catching that Ruth! The peanut butter going in with the eggs and sugar. I’ll fix that now!
I adore these fluffernutter bars!
Hi Rachel! Thank you for this! I have all of the stuff in my pantry right now minus the fluff. Do you think I could use regular mini marshmallows?
You could, but they have the tendency to disappear in baked goods. You could try sprinkling some on top about 5-7 minutes before the bars are done and letting them melt on top!
Oh YUM! These look delicious. I can eat a boatload of these. :D
oh, these look incredible! i rarely pair peanut butter with marshmallows {don’t think i’ve ever had a fluffernutter sandwich…!!!} but love, love the delicious combo. a must-try for me this summer for sure! :)
Gosh, I honestly have not thought about a fluffernutter sandwich in years! Now I feel like I’ve missed so much. I’ll just have to make an extra large batch of these bars to make up for it… :)