Fluffernutter Cookies

Fluffernutter Cookies bring all the nostalgic magic of that classic peanut butter and marshmallow sandwich straight into a warm, chewy cookie! These soft peanut butter cookies hide a sweet, gooey marshmallow fluff center that melts into pure comfort with every bite.

Love More Cookies? Try My Carrot Cake Cookies or this Lemon Cranberry Cookies next.

Why You’ll Love This Recipe

Soft, chewy, and irresistibly sweet, these cookies combine creamy peanut butter and gooey marshmallow for the ultimate nostalgic treat. Each bite is rich, buttery, and perfectly balanced — a fun twist on the classic fluffernutter sandwich.

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Ingredient List

For the Peanut Butter Cookies:

• ½ cup (129 g) creamy peanut butter
• ½ cup (1 stick / 113 g) unsalted butter, room temperature
• 1 cup (200 g) light brown sugar, packed
• 1 large egg, room temperature
• 1 teaspoon vanilla extract
• 1½ cups (187.5 g) all-purpose flour
• 1 teaspoon cornstarch
• ½ teaspoon kosher salt

For the Filling:

• 1 cup marshmallow fluff (or marshmallow creme)

Why These Ingredients Work

Creamy peanut butter creates that classic fluffernutter flavor and adds moisture and richness to the cookies. The oils in peanut butter also help keep these cookies incredibly soft.

Brown sugar (instead of white) gives these cookies a deeper, more caramel-like sweetness and helps them stay extra chewy. The molasses in brown sugar also adds moisture.

Cornstarch is my secret weapon here! It creates a lighter, more tender crumb and prevents the cookies from spreading too much while baking.

Room temperature butter and egg mix more smoothly into the dough, creating an even texture throughout. Cold ingredients can make the dough lumpy and uneven.

Marshmallow fluff is the star of the show—it stays wonderfully gooey even after baking and creates that iconic sweet, fluffy center that makes these cookies so irresistible.

Essential Tools and Equipment

• Large mixing bowl
• Hand mixer or stand mixer
• Measuring cups and spoons
• Two large baking sheets
• Parchment paper
• 2-tablespoon cookie scoop
• Two spoons (for adding marshmallow fluff)
• Piping bag (optional, for cleaner marshmallow application)
• Cooling rack

How To Make Fluffernutter Butter Cookies

Preheat Your Oven

Preheat the oven to 350°F and line two large baking sheets with parchment paper. Don’t skip the parchment—it prevents sticking and makes cleanup a breeze!

Cream the Wet Ingredients

In a large bowl, combine peanut butter, butter, and brown sugar. Using a hand mixer, beat the mixture until it’s smooth and creamy, about 2-3 minutes. You want it light and fluffy—this creates air pockets that make the cookies tender.

Add Egg and Vanilla

Scrape down the sides of the bowl to make sure everything’s incorporated. Add the egg and vanilla and mix until just combined, about 30 seconds. Don’t overmix here—you just want everything blended together.

Add Dry Ingredients

Add the flour, cornstarch, and salt to the bowl all at once.

Mix the Dough

With the mixer on low speed, incorporate the dry ingredients until just combined, 30 seconds to 1 minute. The dough should come together but still look slightly crumbly—that’s perfect! Overmixing at this stage can make tough cookies.

Shape the Dough

Using a 2-tablespoon cookie scoop, drop portions of dough onto your work surface (not the baking sheet yet). Using your hand, flatten each dough ball into a flat disk shape about 3 inches across. This makes it much easier to add the filling and seal the cookies!

Add the Marshmallow Filling

Here’s where it gets fun! Using two spoons (to keep your hands from getting sticky), add about 1 tablespoon of marshmallow fluff to the center of each disk of dough. If you prefer, you can add the fluff to a piping bag and pipe neat dollops onto each dough disk—much cleaner!

Seal the Cookies

Carefully bring the edges of the dough up and around the marshmallow fluff, pinching and sealing to completely cover the filling and form a ball. Make sure there are no gaps or the marshmallow will leak out during baking. Place each sealed cookie on the lined baking sheets, spacing them about 2 inches apart.

Bake

Bake the cookies for 10-12 minutes, or until the edges are golden brown. Watch them carefully during the last few minutes—you want the cookies baked through but the marshmallow shouldn’t burn or burst through.

Rest Before Serving

Let the cookies rest on the baking sheets for 10-15 minutes before transferring to a cooling rack. This resting time is crucial! It allows the cookies to set properly and the marshmallow filling to cool just enough so they don’t fall apart when you move them.

You Must Know

Room temperature is non-negotiable. Cold butter won’t cream properly with the sugar, and cold eggs can cause the dough to seize up. Let them sit out for about 30 minutes before you start baking.

Personal Secret: I always make my dough disks slightly thicker around the edges than in the center. This extra dough helps seal the marshmallow completely and prevents leaks during baking.

The marshmallow will expand as it heats up, so don’t overfill! One tablespoon is the sweet spot—any more and you’ll have marshmallow volcanoes.

Pro Tips & Cooking Hacks

• Sticky situation? Lightly dust your hands with flour when sealing the cookies if the dough is too sticky to handle.
• Even baking: Rotate your baking sheets halfway through baking time for perfectly even cookies.
• Size matters: Using a cookie scoop ensures all your cookies are the same size, which means they’ll all bake at the same rate.
• Don’t overbake: These cookies continue cooking on the hot pan after you remove them from the oven. Take them out when the edges are just golden but the centers still look slightly underdone.
• Chill for cleaner slicing: If you want to see that beautiful marshmallow center in photos, chill the cookies for 15 minutes before cutting one in half.

Flavor Variations & Suggestions

Chocolate Drizzle: Melt some chocolate chips and drizzle over cooled cookies for extra decadence.

Crunchy Style: Use crunchy peanut butter instead of creamy for added texture and peanut chunks throughout.

Mini Marshmallow Version: Substitute 4-5 mini marshmallows for the marshmallow fluff if that’s what you have on hand.

Chocolate Peanut Butter: Add 2 tablespoons of cocoa powder to the dough for chocolate peanut butter cookies with marshmallow centers.

Nutella Twist: Replace half the peanut butter with Nutella for a chocolate-hazelnut variation.

Make-Ahead Options

These cookies are perfect for planning ahead! You can prepare the dough, shape it into balls (without the filling), and freeze them for up to 3 months. When you’re ready to bake, thaw the dough disks, add the marshmallow filling, seal, and bake as directed—you might need to add 1-2 extra minutes to the baking time.

You can also freeze the fully assembled (but unbaked) stuffed cookies on a baking sheet, then transfer them to a freezer bag once solid. Bake from frozen, adding 2-3 minutes to the baking time.

Recipe Notes & Baker’s Tips

The cornstarch in this recipe isn’t just filler—it’s what gives these cookies their incredibly soft, tender texture. Don’t skip it!

If your marshmallow fluff is too thick to work with easily, you can microwave it for about 10 seconds to soften it slightly. Just don’t overheat or it will become too runny.

Make sure you’re using marshmallow fluff or marshmallow creme—not melted marshmallows. They have different textures and melted marshmallows won’t stay gooey inside the cookies.

Serving Suggestions

These cookies are perfect warm from the oven when the marshmallow center is extra gooey! Serve them with a cold glass of milk for the ultimate comfort food experience. They’re also wonderful alongside hot coffee or as an after-school treat with the kids.

For parties or gatherings, arrange them on a pretty platter and watch them disappear. You can even sandwich two cookies together with extra marshmallow fluff for an over-the-top dessert.

How to Store Your Fluffernutter Butter Cookies

Store these cookies in an airtight container at room temperature for up to 5 days. They stay wonderfully soft and the marshmallow center remains gooey!

For longer storage, freeze the baked cookies in a freezer-safe container or bag for up to 3 months. Thaw at room temperature for about 30 minutes before serving, or warm them in the microwave for 10-15 seconds to make that marshmallow center gooey again.

Reheating tip: Pop a cookie in the microwave for 8-10 seconds to warm it up and make the marshmallow filling extra melty and delicious!

Allergy Information

Contains: Peanuts, dairy (butter), eggs, gluten (wheat flour)

Dairy-free option: Substitute vegan butter and use a dairy-free marshmallow fluff alternative (most marshmallow fluff is naturally dairy-free, but always check labels).

Gluten-free option: Use a 1:1 gluten-free baking flour blend in place of all-purpose flour. The texture will be slightly different but still delicious.

Egg-free option: Try using a flax egg (1 tablespoon ground flaxseed + 3 tablespoons water, let sit 5 minutes) though the texture will be slightly denser.

Nut-free option: Substitute sunflower seed butter or soy nut butter for the peanut butter to make these nut-free. Note that sunflower seed butter can sometimes turn the cookies slightly green due to a chemical reaction—it’s harmless but might look unusual!

Questions I Get Asked A Lot

Why did my marshmallow leak out during baking?

This usually happens when the dough isn’t sealed completely around the marshmallow. Make sure to pinch the edges really well and check for any gaps before placing them on the baking sheet. Also, don’t overfill—stick to about 1 tablespoon of fluff per cookie.

Can I use crunchy peanut butter instead of creamy?

Absolutely! Crunchy peanut butter works great and adds nice texture to the cookies. The texture will be slightly different, but they’ll still be delicious.

My cookies spread too much—what went wrong?

This usually means your butter was too soft or melted. Make sure it’s at room temperature but still holds its shape. Also, make sure you’re measuring your flour correctly by spooning it into the measuring cup and leveling it off—too little flour can cause spreading.

The marshmallow hardened when my cookies cooled—is that normal?

The marshmallow will firm up slightly as it cools, but it should still be soft and slightly gooey. If it’s rock hard, you may have overbaked the cookies slightly. A quick 10-second zap in the microwave will soften it right back up!

💬 Tried this recipe? Leave a comment and rating below! I’d love to hear how your Fluffernutter Butter Cookies turned out!