Ooey, gooey soft rice krispie treats are loaded with creamy peanut butter and sweet marshmallow fluff for the perfect fluffernutter flavor! All you need are 5 ingredients and 30 minutes. Next time try my fluffernutter cookies or thick and chewy fluffernutter bars.

Here’s the thing about these fluffernutter rice krispie treats: there is nothing healthy about them and they’re everything I wanted them to be. They’re soft, and ooey, and gooey, and taste like I covered a fluffernutter sandwich with cereal.
Okay, that doesn’t sound appealing or particularly delicious, but you’ll just have to trust me. These are delicious.

In today’s edition of “Why Can’t Leslie Just Leave Things Alone”, I needed to level up the classic rice krispie treats. The base recipe that you find on the side of the Rice Krispies box makes a perfect decent treat, but it’s just not enough for me. They need to be softer and butterier.
So, I solved those problems by adding more marshmallows and more butter. But I still wanted more flavor. I was just… bored.

You all love fluffernutter recipes!
Recently I’ve been digging into my site analytics to see what my audience (that’s you!) has been loving lately, and the fluffernutter cookies and fluffernutter bars are consistently near – or at – the top of the list.
So, I figured… if you love those fluffernutter recipes, maybe you’d love another one. And rice krispie treats are already chock full of marshmallows, so all I’d need to do is add peanut butter!
Not so fast, Leslie.

Marshmallow fluff makes these bars super soft
Marshmallows and marshmallow fluff don’t have the same flavor, so just adding peanut butter was underwhelming. What it really needed was the addition of both peanut butter and fluff. On top of the marshmallows.
And you know what? Let’s add some more mini marshmallows for fun.
That resulted in the softest and most flavorful rice krispie treats I’ve ever made. And it’s strong with the fluffernutter flavor I wanted.

Tips for slicing rice krispie treat bars
I’m going to share a little secret with you: when I pull these out of the pan, I slice off the edges to get the corners squared so no one gets a weird, sloped, lopsided piece.
And then I eat those cut off pieces. I consider it payment for my time. Plus, you know, taste testing.

Not a secret, but a helpful tip: slicing bars like these are infinitely easier when I use a rocking pizza cutter (affiliate link) versus a large knife. It’s big enough to span the width and the length of the bars, so you get one long, even cut.
Plus, it’s easier on your cutting boards because you just rock the blade from side to side, instead of digging in and dragging a knife. Win-win.
Let’s stare at the puddles of marshmallow fluff for a minute.
They’re a big contributor to the softness of these bars.


Add mini marshmallows
The intact mini marshmallows are a nice little surprise when you encounter them. That’s why I save a cup or two of marshmallows to add right at the end.
If you don’t want to add them because you hate good things, that’s fine, too.

Are they really sticky and messy?
Surprisingly, they’re not overly sticky and impossible to eat! That was a sacrifice I was going to be willing to make for the flavor I wanted.
You will, however, still want to store any leftovers in an airtight container between layers of parchment paper just to keep them from sticking together.
But you know, for the purposes of food photography, stacking them without parchment paper is a-okay.
Do as I say, not as I do.


How to store rice krispie treats
You can store them at room temperature between layers of parchment paper in an airtight container for 2 days.
You can also store them in the freezer for up to 1 month – again, in an airtight, freezer-safe container between layers of parchment paper.
To defrost, just let them sit on the counter at room temperature for about 30 minutes before serving. Due to the marshmallow fluff, it tends to take a little bit longer than your typical Rice Krispie Treats.
If you want more peanut butter…
- Fluffernutter Cookies
- Fluffernutter Bars
- Easy Peanut Butter Oreo Fudge
- Chocolate Peanut Butter No Bake Cookies
- Chocolate Chunk Peanut Butter Cookies
- Peanut Butter Espresso Cookies
- No Bake Cookie Overnight Oats
- Buckeye Balls
- Peanut Butter Banana Bread with Salted Chocolate Chips by Hunger Thirst Play
- Nutter Butter Waffles by Whitney Bond
- No Bake Peanut Butter Pie by Spicy Southern Kitchen
After you’ve made this recipe, please consider coming back to share your experience with others by leaving a comment below with a star rating!

Fluffernutter Rice Krispie Treats
Ingredients
- 6 cups Rice Krispies cereal
- 6 tablespoons unsalted butter
- 6 cups mini marshmallows, divided
- 1 cup creamy peanut butter
- 7.5 ounce container of Marshmallow Fluff
- Pinch of salt, if your peanut butter doesn't have any
Instructions
- Prep a 9x13 baking pan with parchment paper so that the edges hang over the sides of the pan, and then spray with nonstick spray. Set aside.
- Pour Rice Krispies into a large bowl and set aside.
- In a medium saucepan, melt butter over low heat. Add 4 cups mini marshmallows and heat, stirring frequently, until melted and mostly combined - it's okay that it's not fully incorporated, it's better that way!
- Turn off heat, add peanut butter and stir to combine. If the peanut butter you're using doesn't have added salt, you can add a pinch of salt at this point and stir to combine.
- Immediately pour peanut butter mixture into the bowl of Rice Krispies, add Fluff and remaining 2 cups mini marshmallows and stir to coat and combine.
- Turn out into prepared baking dish and press down into an even layer.Tip:If you have another 9x13 pan, you can use the bottom of that pan to press into the top of your dish for an easy way to get it evenly distributed! You can also spray your hands with a little nonstick spray and use your palms to press it down, or place another piece of parchment paper on top before using your hands to press it down.
- Let set for at least 15 minutes, and then slice into 12 large bars. Serve and enjoy!
Heather L.
If you like peanut butter, you must make these. OMG. Only difference I did was brown the butter before adding anything.
Leslie Kiszka
You’re a smart person, Heather! :) That sounds faaaaaaantastic.
Michayla
This was absolutely perfect! I will never make regular rice krispies again.. They are gooey but arent oberly sticky to the point they stick to your hands.. I had a bag of jet puffed marshmallows but i was a handful short so i used store brand marshmallows.. For some reason the store brand ones dont melt like the jet puffed do.. I ended up having a couple marshmallows that never melted which tasted really great anyways… This will be a favorite in my house forever.
Leslie Kiszka
So glad that you liked them!
Ea Gilmore
Can you only use Fluff? How would that change the outcome (texture, firmness, etc)? If you can, how much would you use to replace the marshmallows? Thx!
Leslie Kiszka
I’m not sure what you’re planning to swap the Fluff with, but I’ve only ever made/tested this recipe with Fluff so I can’t speak to the results using anything else – sorry!
Ea
Sorry! I was unclear. In the pot when you’ve melted the butter you say to use marshmallows. I wonder if you could use marshmallow fluff instead. Or would that change the outcome of the recipe. Then use the fluff again like the recipe calls for.
Leslie Kiszka
Ohhhhh, I see what you mean! Honestly, I don’t know – but my gut tells me it likely wouldn’t work as well.
aj
The divided 6 cups of marshmallows is divided into 4 cups and 1 cup. One of these numbers is incorrect. Can anyone tell me which one?
Leslie Kiszka
My apologies! That was supposed be divided into 4 cups in the initial mix, and 2 cups for the end. Just updated the recipe card with the correction :) But for what it’s worth, 5 cups and 1 cup would work well, too!
cf
Instruction #4 doesn’t form a complete sentence – seems cut off after ” If the peanut butter you’re using doesn’t…” – doesn’t what?
Leslie Kiszka
Thanks for letting me know there was an issue with the recipe card rendering in full – yikes! Just got that fixed – that step is to add salt if the peanut butter you’re using doesn’t have added salt and you’d like to add some yourself.
Gail Norden
Delicious. I separated the batch into half and added mini chocolate chips after it cooled a little but before I spread it. Now I’m wondering how it would be if I made the plain version, flattened half it on the cookie sheet, spread jam on top them put the rest on top.
Leslie Kiszka
Ooo, that sounds good! Thanks for coming back to leave a comment and rating, Gail!
Whitney Bond
I looooove all the marshmallow goodness in these!!