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Fluffernutter Bars mix smooth peanut butter and fluffy marshmallow for a chewy, tasty treat. They're great for a lazy weekend or an afternoon snack that takes you back to simpler times.
I whipped these up after craving that classic peanut butter and marshmallow combo. It came together fast and became a hit when I shared it around.
Ingredients
- Flour: gives the bars a solid yet tender base. Fresh and fine flour works best.
- Baking powder: just enough to puff up the bars without making them cakey so they stay chewy
- Salt: boosts all the flavors. I prefer fine sea salt for evenness
- Butter (unsalted): adds richness. Soften it to room temp so it mixes smoothly
- Brown sugar: brings a deep molasses touch that pairs well with peanut butter
- White sugar: adds the right kind of sweetness and chewiness
- Peanut butter (smooth): makes the bars creamy and smooth. Natural kinds without extras taste best
- Large eggs + yolk: help hold the dough together and keep it moist
- Marshmallow fluff: the sweet topping that gives these bars their charm. Use a fresh, fluffy jar
How To Make
- Heat Up Oven
- Get the oven to 350°F and place the rack in the middle so things bake evenly and don’t burn underneath.
- Prep Your Pan
- Line a 9x13 pan with parchment, leaving extra on the sides for easy lift out later. You can use foil and grease it lightly too so nothing sticks and clean up is easier.
- Combine Dry Stuff
- Whisk flour, baking powder, and salt together in a bowl. This gets the leavening spread evenly, which helps the texture.
- Beat Sugars and Butter
- In a big bowl, beat the softened butter, brown sugar, and white sugar until it’s light and fluffy. This adds air making the bars tender.
- Mix In Peanut Butter and Eggs
- Stir in smooth peanut butter until it’s all mixed. Then add the eggs and yolk and keep mixing until smooth and thick.
- Add the Flour Mix
- Turn the mixer to low and slowly add the flour mix in two goes. This avoids a flour cloud and keeps the dough nice without overbeating.
- Save Some Dough
- Pull out about a cup of dough and set it aside. You’ll use this part as your topping later.
- Press Base Layer
- Pat the rest of the dough evenly into the lined pan using your hands or a spatula so it bakes evenly.
- Bake Base
- Bake for 25 minutes until it’s set and slightly golden on top. This seals the base before we add the fluff.
- Spread Marshmallow Fluff
- Take the pan out but keep the oven on. Smooth the whole jar of marshmallow fluff over the warm base so it spreads nicely.
- Bake Again Briefly
- Pop the pan back in for a few minutes to melt the fluff just a bit for that gooey top, without it turning brown.
- Cool and Slice
- Let the bars cool in the pan completely. Use the parchment edges to lift them out gently, then cut into pieces to enjoy.
The marshmallow fluff layer is my favorite part. It reminds me of sunny summers and sharing Fluffernutter sandwiches with my brothers. The way the fluff melts over warm peanut butter brings back great memories.
Keep It Fresh
Keep extra bars in an airtight container at room temp for up to three days or in the fridge for a week. Let them warm up before eating so they stay soft. They freeze well too if you wrap them tight. They’ll last a couple of months that way.
Swap Ingredients
If you want crunch, swap smooth peanut butter for crunchy. Almond or sunflower seed butter both work great for a twist. Use coconut oil instead of butter to skip dairy, but it won’t be quite as rich.
How To Serve
Pair these bars with a cold glass of milk or a scoop of vanilla ice cream for a quick dessert. You can also chop them up and sprinkle over yogurt or oatmeal for a peanut butter kick.
Backstory
The Fluffernutter started as a sandwich popular in New England that mixes peanut butter and marshmallow fluff. This bar version keeps that old-school vibe while making a fun handheld treat.
These bars offer comforting flavors with a chewy base and a sweet marshmallow top that hits the spot every time.
Frequently Asked Cooking Questions
- → What makes these bars stay together well?
Butter mixed with brown and white sugar, plus eggs, gives the bars a chewy but firm feel after baking.
- → How do I stop the bars from sticking during baking?
Put parchment paper or foil in the pan and lightly grease it so the bars come out without sticking.
- → Can I swap smooth peanut butter for crunchy?
You can use crunchy peanut butter for some bite, but smooth peanut butter helps the bars hold together and stay even.
- → Is baking the bottom layer first really needed?
Baking that bottom part first helps it firm up and keeps the marshmallow fluff from soaking in, so each layer stays separate.
- → What’s the best way to keep these bars fresh?
After they cool, keep the bars in a sealed container at room temp or in the fridge to make them last longer.