Reese’s Pieces Peanut Butter Fluffernutter Cookies with Peanut Butter Buttercream
This post may contain affiliate links.
What’s a fluffernutter? If you have to ask, you have major eating to do to make up for lost time.
Fluffer is marshmallows. Nutter is peanut butter. Two of my favorite ingredients in one cookie.
And they’re some of the best cookies I’ve ever made.
For the cookies, I used my recipe for Reese’s Pieces Soft Peanut Butter Cookies. It’s been very popular with readers and the cookies are supremely soft, squishy, tender, and moist, with just a tiny amount of chewiness.
Reese’s Pieces and chocolate chips are abundantly studded throughout the very peanut buttery dough.
No need to wonder if these are peanut butter cookies after tasting the peanut butter intensity. Some peanut butter cookies recipes are so blah and lackluster, but not these.
The chocolate chips melt, and get gooey, while the Reese’s Pieces add crunchy texture. I love biting into their candy-coated shells amidst the soft, buttery dough.
After the cookies have baked for about 6 minutes, pull them out of the oven, top with half of a large marshmallow, and bake for another couple minutes. Just long enough to soften the marshmallows so they start to melt and a bit. Don’t let them turn into puddles of goo or develop color.
After the cookies cool a bit, top them with peanut butter buttercream frosting. It’s the literal icing on the cake.
Or on the cookie.
It’s creamy, fluffy, peanut buttery, and buttery, with just the right balance of salty-and-sweet. I want to put it on everything. Even broccoli.
The cookies are a peanut butter lover’s dream: Peanut butter in the dough, in the Reese’s Pieces, and in the buttercream.
And when mixed with chocolate chips and marshmallows, the range of flavors makes them irresistible.
The texture is something from my dreams. The cookie dough is supremely soft, the Reese’s Pieces add crunch, the chocolate chips are melty and soft, and the marshmallows are like biting into clouds.
Clouds that are topped with frosting from the heavens. It’s light, soft, fluffy, and lends even more squishiness.
As I was stacking the cookies and the frosting and marshmallows were squishing down, all I could think was, Don’t Squeeze the Charmin.
I finished them off with a pinch of chocolate sprinkles.
As if they needed anything else going on, but why not.
- 1 large egg
- 1 cup light brown sugar, packed
- 3/4 cup creamy peanut butter (do not use homemade or natural peanut butter; use Jif, Skippy, or similar)
- 1/2 cup unsalted butter, softened
- 1 tablespoon vanilla extract
- 1 3/4 cups all-purpose flour
- 3/4 teaspoon baking soda
- pinch salt, optional and to taste
- 1 cup Reese’s Pieces
- 1 cup semi-sweet chocolate chips
- about 12 to 15 large marshmallows, each sliced in half
Peanut Butter Buttercream Frosting
- 4 tablespoons unsalted butter, softened (half of one stick)
- about 1/3 cup creamy peanut butter
- 3/4 teaspoon vanilla extract
- about 1 cup confectioners’ sugar
- pinch salt, optional and to taste
- splash of cream or milk, only if necessary to achieve desired consistency
- chocolate sprinkles, optional for garnishing
- For the Cookies – To the bowl of a stand mixer fitted with the paddle attachment (or large bowl and electric hand mixer), cream together the first 5 ingredients (through vanilla) on medium-high speed until light and fluffy, about 5 minutes.
- Stop, scrape down the sides of the bowl, and add the flour, baking soda, optional salt, and mix on low speed until just incorporated, about 1 minute; don’t overmix.
- Add the Reese’s Pieces, chocolate chips, and mix until just incorporated.
- Preheat oven to 350F, line a baking sheet with a Silpat or spray with cooking spray. Place mounds on baking sheet, spaced at least 2 inches apart (I bake 8 cookies per sheet) and bake for about 6 1/2 minutes. Cookies will be at the extremely under-done point.
- Remove tray from oven, and place a marshmallow halve on top of each cookie, pressing it down lightly into the cookie. Don’t press too hard and flatten the cookie.
- For the Peanut Butter Buttercream Frosting – To a medium mixing bowl, combine the butter, peanut butter, vanilla, and whisk to combine or beat with an electric mixer until smooth.
- Slowly add the sugar, optional salt, and mix until smooth. Based on desired consistency of frosting, add the sugar slowly, and if you’ve added too much and the frosting gets too thick, add a splash of cream or milk to thin it.
- Add a generous dollop (2+ tablespoons) to each cookie, and smooth it, as desired, with a knife or spatula.
- Optionally garnish with sprinkles.
- Cookies will keep airtight at room temperature for a few days or in the refrigerator for up to 1 week. I’m okay with leaving buttercream at room temperature for a couple days; if you aren’t, refrigerate the cookies, knowing they won’t have the gooey factor. Unbaked cookie dough can be stored airtight in the refrigerator for up to 5 days, or frozen for up to 4 months, so consider baking only as many cookies as desired and save the remaining dough to be baked in the future when desired.
Peanut Butter Chocolate Chunk Cookies – One of the most popular recipes on my site, ever
Peanut Butter Cocoa Krispies Smores Bars – (almost no-bake)
Peanut Chewy Payday Bars (almost no-bake)
Marshmallow Peanut Butter Double Chocolate Pillowtop Bars (GF with Vegan options)
Browned Butter Rice Krispies Treats – The best RKTs I have ever had. Double the butter and it’s browned, for great flavor and soft, buttery, chewy bars
Homemade Cinnamon Sugar Graham Crackers Smores – I love using big, fluffy marshmallows in them
Peanut Butter Comfort – My cookbook featuring over 100 Peanut Butter Recipes
Fluffernutter fan? What’s your favorite peanut butter cookie?
We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com.