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Fluffernutter Bars take the peanut butter and marshmallow sandwich idea and turn it into a chewy dessert bar. The base is soft, salty-sweet peanut butter dough. The middle stays gooey with marshmallow creme and a little extra peanut butter.
I like these for bake sales and family trays because they cut into sturdy squares, but they still have that sticky marshmallow pull when you bite in. The big trick is patience. Let the pan cool before you slice.
Peanut Butter Dough Lineup
Use the kind of pantry peanut butter you would spread on toast. A no-stir creamy peanut butter blends into the dough cleanly and gives the bars that classic sandwich flavor.
Marshmallow creme is sticky, so measure it with a greased spatula or spoon. The official Marshmallow Fluff history is worth a quick read if you like the old-school New England roots of this flavor combo.
- Creamy peanut butter. Gives the dough its nutty flavor and keeps the crumb soft.
- Unsalted butter. Adds richness and helps the bars bake up tender instead of dry.
- Light brown sugar. Brings moisture and a mild caramel note that fits peanut butter well.
- Egg. Holds the dough together and gives the bars a chewy bite.
- Vanilla extract. Rounds out the peanut butter and marshmallow sweetness.
- All-purpose flour. Gives the bars enough structure to slice into squares.
- Marshmallow creme. Creates the soft, gooey fluffernutter layer.
- Salt. Keeps the bars from tasting flat or overly sweet.
Layer, Bake, Cool
- Prepare the pan. Line an 8-inch square pan with parchment so you can lift the cooled bars out cleanly.
- Mix the wet base. Beat butter, peanut butter, and brown sugar until smooth. Add the egg and vanilla and mix again.
- Finish the dough. Stir in flour, baking powder, and salt just until no dry streaks remain. The dough will be thick.
- Build the layers. Press about two-thirds of the dough into the pan. Spread on marshmallow creme, drizzle with warm peanut butter, then flatten small pieces of remaining dough over the top.
- Bake the bars. Bake at 350°F until the edges are golden and the center is set but still soft, about 26-30 minutes.
- Cool before slicing. Let the pan cool for at least 1 hour. Chill briefly if you want sharper edges.
Why Fluffernutter Bars Work
The best part of these Fluffernutter Bars is the contrast. The peanut butter dough bakes into a chewy shell around the marshmallow creme. The edges get lightly golden, while the center stays soft and a little sticky.
Do not spread the top dough into a sealed lid. Small gaps let the marshmallow peek through and bubble a bit. Those pockets look good after baking and keep each square from feeling heavy.
If peanut butter desserts are your thing, try these alongside Peanut Butter Cookie Bars or No-Bake Peanut Butter Buckeye Bars for a tray with different textures.
The Sticky Middle Trick
Marshmallow creme does not spread like frosting. It pulls, stretches, and sticks to everything. Grease your spatula lightly before spreading it over the bottom dough. You can also dollop it across the pan first, then nudge the dollops together.
A small drizzle of warmed peanut butter over the marshmallow layer makes the filling taste fuller. It also helps the top dough settle without smashing all the creme to the edges.
Do not taste raw dough while you work. The FDA has plain guidance on raw flour and safe handling in its food safety resources.
How To Avoid Dry Bars
Pull the pan when the edges are golden and the top no longer looks wet. The center should still feel a little soft. It will firm as it cools, and that carryover heat is part of the recipe.
Overbaking is the main way these bars lose their charm. Once the marshmallow layer gets too hot for too long, it can turn chewy instead of gooey. Start checking at 26 minutes if your oven runs warm or your pan is dark metal.
Smart Swaps And Add-Ins
For more crunch, press chopped roasted peanuts into the top before baking. For a chocolate version, scatter 1/2 cup chocolate chips over the marshmallow layer before adding the top dough. Keep the amount modest so the bars still taste like peanut butter and fluff.
If you want a bigger dessert-bar spread, these sit well next to Magic Cookie Bars and Toasted Marshmallow Hot Chocolate Bars. The flavors overlap enough to make sense, but the textures are different.
Storage And Serving Notes
Let the bars cool fully before covering them. Trapped steam can make the top tacky. Once cool, keep them airtight at room temperature for up to 3 days or in the fridge for up to 5 days.
For serving, cut smaller squares than you think you need. These are sweet and rich. A 16-square pan feels right for parties, while 9 larger squares are better for a casual dessert with coffee.
Summary
For the cleanest bars, use shelf-stable creamy peanut butter, line the pan with parchment, and cool the baked slab completely before cutting.
FAQs
- What are Fluffernutter Bars?
Fluffernutter Bars are dessert bars inspired by the classic peanut butter and marshmallow creme sandwich. This version bakes those flavors into a chewy peanut butter cookie bar with a soft marshmallow layer in the middle.
- Can I use natural peanut butter?
I do not recommend the runny natural kind for these bars. It can make the dough greasy and crumbly. Use a smooth, no-stir creamy peanut butter for the best texture.
- Can I use mini marshmallows instead of marshmallow creme?
Marshmallow creme gives the gooey ribbon that makes these bars feel like a fluffernutter. Mini marshmallows will puff, melt unevenly, and may leave sticky pockets. If that is all you have, use them sparingly and expect a different texture.
- How do I cut clean slices?
Cool the bars completely, then lift them out with the parchment. Use a sharp knife lightly coated with nonstick spray. Wipe the blade between cuts if marshmallow starts to drag.
- How should I store Fluffernutter Bars?
Store them in an airtight container at room temperature for up to 3 days. If your kitchen is warm, refrigerate them so the marshmallow layer stays tidy. Let chilled bars sit for 10 minutes before serving.
- Can I freeze these bars?
You can freeze them, but the marshmallow layer may lose some of its soft pull after thawing. Wrap individual squares tightly and freeze for up to 1 month. Thaw at room temperature before serving.
- What should I serve with them?
These bars are rich, so cold milk or hot coffee works well. For a dessert tray, pair them with brighter bars like lemon bars or fruit-forward crumble bars.
