Peppermint Bark Cookie Bars

Soft, buttery cookie bars topped with swirls of marshmallow buttercream, crushed peppermint, and a drizzle of chocolate—these Peppermint Bark Cookie Bars taste like Christmas in every bite.

The Perfect Holiday Treat

Peppermint bark is one of those holiday treats I look forward to every year—but instead of layering chocolate, this year I decided to turn those flavors into a bakery-style cookie bar.

The base starts with my tried-and-true snickerdoodle bar dough (my most requested cookie bar, by the way), baked soft and chewy, then topped with fluffy marshmallow buttercream, Oreo bits, crushed peppermint chips, and a drizzle of milk chocolate ganache.

Yeah, I know. Sounds divine. . .and it is! (Hey, if you're looking for an incentive to fall off your low-carb plan, this will do the trick!)

The result is festive, sweet, and perfectly balanced—peppermint without being overpowering. And, if I do say so myself, one of the finest things I've ever baked.

And that's saying a lot. Because, well, I bake. . .a lot.

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Peppermint Bark Cookie Bar Ingredients

You'll find a printable recipe card at the bottom of this post, as always, but I'm going to go ahead and give you a quick peek at what you'll need. These are simple ingredients you might already have on hand.

Cookie Bar Base

• 1 cup salted butter, room temperature
• 1 cup granulated sugar
• ⅔ cup packed light brown sugar
• 2 large eggs
• 1 teaspoon pure vanilla extract
• 2 cups all-purpose flour

Marshmallow Fluff Frosting

• ½ cup (1 stick) room temperature butter (salted or unsalted, your choice)
• ½ cup Crisco
• 1 cup powdered sugar
• 1 7-ounce container marshmallow fluff
• 1 teaspoon pure vanilla extract

Toppings

• 1 cup Peppermint baking chips or crushed peppermint candy
• 4 Oreos (crushed, optional)
• 3-4 tablespoons milk chocolate ganache (for drizzling)

Note: The Marshmallow Buttercream is optional. You can use any frosting you like, including canned frosting, if you're in a hurry!

How to Make Peppermint Cookie Bars

These come together so easily and they're absolutely delicious! What are we waiting for? Let's whip up a batch!

Step 1: Prep

Preheat oven to 350°F.
Line a 9×13-inch baking dish with parchment paper or lightly grease.

Step 2: Make the Cookie Bar Dough

In a large mixing bowl, cream together the butter, granulated sugar, and brown sugar until light and fluffy.

Add the eggs and vanilla extract, mixing until fully incorporated.

Gradually add the flour and mix just until combined. The dough will be thick and soft.

Step 3: Bake

Press the dough evenly into the prepared pan. Use floured hands to press it down as evenly as you can.

Bake for 22–26 minutes, or until the top is set and lightly golden and a toothpick inserted near the center comes out mostly clean.

Allow bars to cool completely before frosting.

Remove bars from pan to continue cooling on parchment paper.

Make the Frosting

Whip the butter and Crisco together until light and fluffy. Add vanilla and powdered sugar and beat until fully incorporated. Add the marshmallow fluff and mix until combined. Color about ¼ of the frosting in bright red. Leave the rest white.

Decorating the Bars

Spread the marshmallow buttercream over the cooled bars, gently swirling the pink and white frosting together for a festive look.

Sprinkle generously with crushed Oreos

Add peppermint chips. (Just eyeball how much you like.) Then drizzle the milk chocolate ganache over the top.

Refrigerate for 15 minutes before cutting into squares.

Serve and enjoy!

Storage Tips

Store Peppermint Bark Cookie Bars in an airtight container at room temperature for up to 2 days, or refrigerate for up to 5 days. Bring to room temperature before serving for the best texture.

Why You’ll Love These Bars

• Soft, chewy cookie base with bakery-style texture. (I promise, the texture is divine!)
• No peppermint extract—just clean, balanced flavors. The contrast of the sugary base and the minty, chocolatey topping? Perfection!
• Marshmallow frosting keeps them light and fluffy. It's literally the icing on the cake! (Er. . .cookie!)
• Perfect for cookie trays, gifting, or holiday parties. You're going to want to add this one to your lineup this holiday season, friends. But if your cookies are going to remain at room temperature for any length of time you might want to make a fully shelf-stable frosting with shortening and marshmallow fluff (no butter).

Variations on this Recipe

I love this recipe so much! There's something about the addition of mint and chocolate to the top of that Snickerdoodle base that really, really works! (Yum!)

But you know me: I love to change things up. So, here are some fun ideas for next time:

• Chocolate chips: It might be fun to add a handful of mini chocolate chips to the top.
• Pretzel pieces: Sweet and salty? Yes, please!
• White chocolate chips: These might be fun, too!
• Holiday M&Ms. (Did you know you can buy holiday M&Ms in mint flavor? If you can't find them, the milk chocolate ones will be fine!

Other Holiday Favorites from Out of the Box

If you enjoy this recipe (and what's not to enjoy?) you're going to love the following:

• Peppermint Bark: This is the original peppermint bark, the candy version, and it's delicious!
• The Ultimate Christmas Cookie Collection: I've got them. . .in spades!
• Old-Fashioned Jelly Nougat Candy: This is a personal favorite, one that dates back to my childhood!

That's it for this post, friends!

I'm so glad you stopped by. If you make these cookie bars and love them, please feel free to leave a review.

Before you go, why not pin some photos to your Pinterest boards?

Janice Thompson is a professional baker, cake designer, and author with over 20 years of experience creating unique cakes and desserts. She’s the creator of Out of the Box Baking, where she shares her favorite doctored cake mix recipes, tutorials, and baking tips. Learn more →