Creamy, gooey, and impossibly chocolatey — these Chocolate Marshmallow Cookie Bars are the kind of dessert that makes weeknights feel like a celebration. With a buttery cookie base, a fluffy marshmallow middle, and a glossy chocolate topping, every bite delivers contrasting textures and deep, comforting flavor. Fun fact: marshmallow crème was originally a medicinal syrup before it became a baking superstar — lucky for us it found its way into dessert bars.
This recipe is special because it’s simple, quick to prepare, and loved by kids and adults alike. If you’ve enjoyed other cookie bar recipes on the blog, you’ll find these just as reliable and satisfying; for more chocolate bar inspiration, check out this similar recipe for chocolate marshmallow cookie bars. Ready to make a batch that disappears fast? Let’s bake!
What is Chocolate Marshmallow Cookie Bars?
What’s in a name? Chocolate Marshmallow Cookie Bars combine two beloved treats into one: a cookie-like base, a marshmallow crème layer, and a chocolate ganache-style top. Who invented it — a midnight snacker with extra marshmallow fluff in the pantry? Perhaps. Why is it called this way — because it’s literally cookie bars with marshmallow and chocolate on top! And yes, these bars prove the old adage “the way to a man’s heart is through his stomach.” Want to impress the people you love (or yourself)? Try this recipe and watch the smiles appear.
Why You’ll Love This:
- Decadent contrast: Soft cookie base, pillowy marshmallow center, and a smooth chocolate topping create a trifecta of textures that’s both comforting and indulgent.
- Budget-friendly baking: Homemade bars use pantry staples and a little chocolate — far less expensive than specialty bakery treats but even more satisfying.
- Flavor versatility: The base is classic cookie dough—brown sugar and vanilla give it a caramelized depth while chocolate chips in the batter add bursts of melty richness. Top with flaky sea salt for a grown-up twist or extra sprinkles for kid-friendly fun.
If you enjoy the fudgy, easy-to-slice textures of our other treats like the chocolate chip cookie dough bars, these will quickly become a rotation favorite. Try them and see why they’re often requested for potlucks and bake sales. Grab your apron and let’s bake!
How to Make:
Quick Overview
This recipe is straightforward and forgiving — no special equipment required. You’ll cream butter and sugars, fold in dry ingredients, bake a cookie slab, spread marshmallow crème, and finish with melted chocolate that sets into a glossy top. Total hands-on time is about 20 minutes, with 20–25 minutes baking and additional chilling or setting time. The standout element is that marshmallow layer: light, sweet, and delightfully gooey between crisp edges and a silky chocolate crown. For another take on cookie bars with ooey-gooey centers, see this take on chocolate chip cookie dough bars at chocolate chip cookie dough bars.
Ingredients
- 1 cup unsalted butter, softened to room temperature
- 1 cup brown sugar, packed
- 1/2 cup granulated sugar
- 2 large eggs, at 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 (mix-ins for the cookie base)
- 2 cups marshmallow crème (also called marshmallow fluff), stirred smooth before spreading
- 2 cups semi-sweet chocolate chips (for topping)
- 2 tablespoons coconut oil or unsalted butter, for melting with the topping chocolate
Directions
- Preheat oven to 350°F (175°C) and grease a 9×13-inch baking dish with butter or nonstick spray. Line with parchment if you like for easy removal.
- In a large bowl, cream the softened unsalted butter, packed brown sugar, and granulated sugar together until light and fluffy — about 2 to 3 minutes using a hand mixer or stand mixer on medium. Scrape the sides as needed.
- Beat in eggs one at a time, mixing well after each addition. Add the vanilla extract and mix until combined.
- In a separate bowl, whisk together the all-purpose flour, baking soda, and salt to ensure even distribution.
- Gradually add the dry ingredients to the wet mixture, mixing on low until just combined. Avoid overmixing to keep the bars tender.
- Fold in 1 1/2 cups chocolate chips by hand, then press the cookie dough evenly into the prepared 9×13-inch baking dish, smoothing the top with a spatula.
- Bake for 20–25 minutes until the edges are golden brown and the center is set. A toothpick in the center should come out mostly clean with a few moist crumbs. Let the cookie base cool completely in the pan — at least 30 minutes.
- Once cool, spread 2 cups of marshmallow crème evenly over the cookie base. Use an offset spatula or the back of a spoon to smooth it into a uniform layer.
- In a microwave-safe bowl, combine 2 cups semi-sweet chocolate chips and 2 tablespoons coconut oil or butter. Microwave in 30-second intervals, stirring thoroughly after each interval, until melted and glossy.
- Pour the melted chocolate over the marshmallow layer and spread evenly with a spatula to cover.
- Allow the bars to set at room temperature for 1 hour, or chill in the refrigerator for 20–30 minutes until firm to the touch.
- Once set, cut into squares and enjoy. Store extras as noted below.
What to Serve With:
- A scoop of vanilla ice cream or a drizzle of salted caramel for contrast.
- Fresh berries or a simple fruit salad to cut through the sweetness.
- Coffee or a bold black tea for balance; for kids, a cold glass of milk is classic.
- For a party, serve alongside other bite-sized bars and cookies to create a dessert platter.
Top Tips for Perfecting:
- Ingredient swaps: Use unsalted butter and add a pinch more salt if using salted butter. For dairy-free, swap coconut oil for butter and use dairy-free chocolate chips.
- Timing: Let the cookie base cool completely before adding marshmallow crème — if it’s warm, the fluff will melt and seep into the cookie.
- Chocolate topping: For an ultra-smooth finish, stir chocolate until completely glossy; overheating leads to graininess.
- Texture tweaks: Press edges slightly with a fork before baking for crisper edges, or trim after baking for neat squares.
- Common mistakes: Don’t overbake the cookie base — remove when center is set but still slightly soft for best texture.
Storing and Reheating Tips:
- Refrigerator: Store bars in an airtight container in the fridge for up to 5 days. The chocolate topping will stay firm and the marshmallow layer stable.
- Freezing: Wrap individual bars in plastic wrap, then place in a freezer-safe bag. Freeze up to 3 months. Thaw in the refrigerator overnight before serving.
- Best reheating: Serve chilled or bring to room temperature. If you prefer warm bars, microwave a single piece for 8–10 seconds — don’t overheat or the marshmallow will become very sticky.
FAQs
What can I use instead of marshmallow crème?
You can use mini marshmallows spread over the warm cookie base and briefly broil to melt and form a layer, but watch carefully to avoid burning. Marshmallow crème gives a smoother, more even layer.
Can I make these ahead for a party?
Yes — make them the day before and refrigerate. They slice neatly and hold up well, making them a great make-ahead dessert.
How do I get a shiny chocolate topping?
Mixing the chocolate with a small amount of coconut oil or butter and melting gently yields a glossy finish. Stir thoroughly until smooth.
Can I use milk chocolate instead of semi-sweet?
Absolutely — use your favorite chocolate. Semi-sweet balances the sweetness of the marshmallow, while milk chocolate will be sweeter and creamier.
Why did my marshmallow layer sink into the cookie base?
If the base was still warm when the marshmallow crème was applied, it can melt into the cookie. Always cool the base completely before spreading.
Conclusion
These Chocolate Marshmallow Cookie Bars are a tried-and-true crowd-pleaser: easy to make, budget-friendly, and utterly satisfying with every gooey, chocolate-kissed bite. They’re perfect for bake sales, potlucks, or a cozy night in with family. If you’d like another take on a marshmallow-topped chocolate cookie bar for inspiration, check out Marshmallow Chocolate Chip Cookie Bars – Averie Cooks for a delicious comparison and extra ideas. Give this recipe a try and share the results — these bars are meant to be enjoyed together.
Chocolate Marshmallow Cookie Bars
Equipment
- Mixing Bowl
- Baking Dish
- Microwave
Ingredients
Ingredients
- 1 cup Unsalted butter, softened At room temperature
- 1 cup Brown sugar, packed
- 1/2 cup Granulated sugar
- 2 large Eggs At 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 Mix-ins for the cookie base
- 2 cups Marshmallow crème Stirred smooth before spreading
- 2 cups Semi-sweet chocolate chips For topping
- 2 tablespoons Coconut oil or unsalted butter For melting with the topping chocolate
Instructions
- Preheat oven to 350°F (175°C) and grease a 9×13-inch baking dish with butter or nonstick spray. Line with parchment if you like for easy removal.
- In a large bowl, cream the softened unsalted butter, packed brown sugar, and granulated sugar together until light and fluffy — about 2 to 3 minutes using a hand mixer or stand mixer on medium. Scrape the sides as needed.
- Beat in eggs one at a time, mixing well after each addition. Add the vanilla extract and mix until combined.
- In a separate bowl, whisk together the all-purpose flour, baking soda, and salt to ensure even distribution.
- Gradually add the dry ingredients to the wet mixture, mixing on low until just combined. Avoid overmixing to keep the bars tender.
- Fold in 1 1/2 cups chocolate chips by hand, then press the cookie dough evenly into the prepared 9×13-inch baking dish, smoothing the top with a spatula.
- Bake for 20–25 minutes until the edges are golden brown and the center is set. A toothpick in the center should come out mostly clean with a few moist crumbs. Let the cookie base cool completely in the pan — at least 30 minutes.
- Once cool, spread 2 cups of marshmallow crème evenly over the cookie base. Use an offset spatula or the back of a spoon to smooth it into a uniform layer.
- In a microwave-safe bowl, combine 2 cups semi-sweet chocolate chips and 2 tablespoons coconut oil or butter. Microwave in 30-second intervals, stirring thoroughly after each interval, until melted and glossy.
- Pour the melted chocolate over the marshmallow layer and spread evenly with a spatula to cover.
- Allow the bars to set at room temperature for 1 hour, or chill in the refrigerator for 20–30 minutes until firm to the touch.
- Once set, cut into squares and enjoy. Store extras as noted below.