Chocolate Marshmallow Cookie Bars

Creamy, gooey, and downright irresistible — these Chocolate Marshmallow Cookie Bars are everything you want in a dessert: a crisp cookie base, a pillowy marshmallow middle, and a glossy chocolate topping that snaps just right. Fun fact: marshmallow crème was originally invented so chocolate marshmallow treats could be made without roasting over a campfire — convenience wins! This recipe is a quick, weeknight-friendly dessert that feels fancy but is simple enough for a baking beginner.

If you enjoy chocolate-forward cookie treats, you might also love my take on Almond Joy Chocolate Cookies, which share the same satisfying chocolatey vibe but with a coconut twist. Give these bars a try the next time you want something crowd-pleasing, quick to prepare, and decadently chocolatey — your family and friends will ask for seconds.

What is Chocolate Marshmallow Cookie Bars?

What’s in a name? Chocolate Marshmallow Cookie Bars sounds like someone took everyone’s favorite campfire s’more, gave it a cookie crust, and served it in squares — and that’s basically it. Why the long name? Because it tells you exactly what to expect: a chocolate-packed cookie base, a marshmallow crème center, and a chocolate topping. Who doesn’t love an honest name?

Did a baker ever say, “Let’s put marshmallow on a cookie and call it magic”? Maybe. Or maybe it’s called this because “the way to a man’s heart is through his stomach.” Try not to laugh while cutting the first piece — these are dangerously shareable. Go on, make them and see for yourself.

Why You’ll Love This

• Meltingly gooey texture: The marshmallow layer creates a light, airy contrast to the crisp cookie base and silky melted chocolate top. Every bite hits multiple textures and temperatures — crunchy, chewy, and smooth.
• Cost-effective and flexible: Making these bars at home is wallet-friendly; a little butter, simple pantry staples, and a jar of marshmallow crème go a long way. You’ll get more servings for less than store-bought specialty bars.
• Flavor crowd-pleaser: Semi-sweet chocolate chips in the dough plus a melted chocolate topping offer deep chocolate flavor without being overly sweet; add flaky sea salt on top if you want a salty-sweet finish.

If you like layered dessert bars, you’ll also enjoy the texture play in my Caramel Chocolate Crunch Bars. Make these bars for a bake sale, a potluck, or a cozy family night — they’re simple, fast, and impressive.

How to Make: Quick Overview

This recipe is straightforward, beginner-friendly, and satisfying. You’ll cream butter and sugars, mix in eggs and vanilla, and fold in flour and chocolate chips for a cookie-style base. After a quick bake, cool completely before layering with marshmallow crème and melted chocolate. The standout element is the marshmallow layer — light and fluffy — balanced by a crisp cookie foundation and rich chocolate top. Prep time: about 15 minutes. Bake time: 20 to 25 minutes. Cooling and setting: 30 to 60 minutes. Total time: roughly 1 hour.

Ingredients

• 1 cup unsalted butter, softened to room temperature
• 1 cup brown sugar, packed
• 1/2 cup granulated sugar
• 2 large eggs, room temperature
• 2 teaspoons vanilla extract
• 2 1/2 cups all-purpose flour
• 1 teaspoon baking soda
• 1/2 teaspoon salt
• 1 1/2 cups chocolate chips (folded into the dough)
• 2 cups marshmallow crème (for spreading)
• 2 cups semi-sweet chocolate chips (for topping)
• 2 tablespoons coconut oil or butter (to melt with the topping chocolate)

Directions

1. Preheat the oven to 350°F (175°C) and grease a 9×13-inch baking dish. Make sure the pan is well-greased or line it with parchment, leaving a little overhang for easy removal.
2. In a large bowl, cream together the softened butter, brown sugar, and granulated sugar until smooth and fluffy. Use an electric mixer on medium speed for about 2 to 3 minutes.
3. Beat in the eggs one at a time, scraping down the bowl after each addition, then stir in the vanilla extract. Mix until fully incorporated.
4. In a separate bowl, whisk together the flour, baking soda, and salt; gradually mix the dry ingredients into the wet ingredients until just combined. Don’t overmix — you want a soft cookie dough.
5. Fold in the 1 1/2 cups of chocolate chips, distributing them evenly through the dough. Press the dough evenly into the greased 9×13-inch baking dish using the back of a spatula or clean hands.
6. Bake for 20 to 25 minutes or until the cookie base is golden brown and a toothpick comes out mostly clean. Avoid overbaking to keep a slightly tender center. Allow the base to cool completely in the pan on a wire rack.
7. Spread the 2 cups of marshmallow crème evenly over the cooled cookie base. If the marshmallow is very stiff, warm it slightly in the microwave for 10 to 15 seconds to make spreading easier.
8. In a microwave-safe bowl, melt the 2 cups of semi-sweet chocolate chips with 2 tablespoons coconut oil (or butter) in 30-second intervals, stirring between each interval, until the mixture is smooth and glossy.
9. Pour the melted chocolate over the marshmallow layer and spread evenly with a spatula. If desired, sprinkle a pinch of flaky sea salt on top.
10. Let the bars set at room temperature for about 30 to 60 minutes or chill in the fridge until firm for easier slicing.
11. Cut into squares and enjoy!

What to Serve With

• A cold glass of milk or hot coffee for contrast and balance.
• Fresh berries or a mixed fruit salad to cut the richness with bright acidity.
• Whipped cream or a scoop of vanilla ice cream for an extra indulgent dessert plate.
• Espresso or a mocha for coffee lovers who want amplified chocolate notes.

Top Tips for Perfecting

• Softened butter matters: Make sure it’s soft enough to cream with sugars but not melted. This creates the best texture in the cookie base.
• Don’t skip cooling: The marshmallow layer spreads best on a completely cooled cookie base; otherwise it will melt and seep.
• Chocolate melting tip: Add the coconut oil or butter to the chocolate while melting to keep the topping smooth and shiny.
• Customize the chips: Use milk or dark chocolate chips to change the flavor profile; white chocolate chips are great for a sweeter twist.
• Avoid overbaking: Pull the base out when it’s just golden — it will continue to set as it cools.

Storing and Reheating Tips

• Room temperature: Store bars in an airtight container at room temperature for up to 3 days. Keep them in a single layer or separate layers with parchment.
• Refrigeration: For longer freshness, refrigerate up to 7 days. Bring to room temperature for 15 to 30 minutes before serving for softer texture.
• Freezing: Freeze cut bars in a single layer on a baking sheet until firm, then wrap individually in plastic wrap and place in a freezer-safe container for up to 3 months. Thaw overnight in the fridge.
• Reheating: For a warm bite, microwave a single bar for 8 to 12 seconds (depending on your microwave) — the marshmallow will soften and the chocolate will be gooey. Avoid overheating.

FAQs

Can I use homemade marshmallow fluff instead of store-bought marshmallow crème?
Yes — homemade marshmallow fluff works beautifully. Make sure it’s smooth and slightly cooled before spreading.

Can I make these bars ahead of time for a party?
Absolutely. You can assemble them a day ahead and refrigerate; bring to room temperature before serving or slice while chilled for neater squares.

What if I don’t have coconut oil for the topping?
Use 2 tablespoons of unsalted butter instead. It adds a nice shine and helps the chocolate set smoothly.

Can I add nuts or other mix-ins?
Yes — chopped toasted pecans or almonds folded into the dough add great texture. You can also sprinkle chopped nuts over the melted chocolate before it sets.

How do I prevent the marshmallow from becoming too gooey?
Cool the cookie base completely and spread the marshmallow crème at room temperature. Chilling the assembled bars helps the layers firm up and makes slicing easier.

Conclusion

These Chocolate Marshmallow Cookie Bars are a perfect blend of textures and flavors — crisp, gooey, and chocoholically satisfying. They’re simple to make, family-friendly, and ideal for sharing at gatherings or enjoying with a cup of coffee. If you want a slightly different take on marshmallow-chocolate bars, check out this reliable recipe for Marshmallow Chocolate Chip Cookie Bars – Averie Cooks for inspiration and variations. Give these bars a try, share them with someone special, and enjoy the smiles that follow.