A quintessential summer dessert, this s’mores cake has rich, fluffy layers of chocolate cake filled with marshmallow cream, graham crumbles, and chocolate ganache and frosted with chocolate marshmallow buttercream. It is a favorite year round but is especially perfect for summer!

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The first time I met him, I knew my husband might be the perfect man for me because of marshmallow. We got ice cream after dinner on our first date. We both got marshmallow sauce on our sundaes and had an actual conversation about how great marshmallow sauce is, and I thought, “This guy knows what’s up.”

Personally, I love marshmallow the most with s’mores. They remind me of camping and summer and watching the stars. Plus, the flavor combination just can’t be beat, imo.

And I’m a devoted lover of all things s’mores. I’ve been sad to an absurd degree ever since Tillamook discontinued their Fireside S’mores ice cream. I’ve made many s’mores inspired desserts over the years.

And this cake is my favorite iteration of reimagined s’mores.

It uses my favorite chocolate cake layers. I then fill it with marshmallow fluff (store bought or homemade—both work!), graham cracker pie crust crumbles, and chocolate ganache drizzle. I then frost it with my most popular recipe: chocolate marshmallow buttercream. That frosting is silky smooth and this wonderful balance of rich chocolate and sweet marshmallow.

Altogether, it’s possibly my favorite cake ever.

Homemade marshmallow or store bought?

I recently discovered how to make marshmallow fluff/cream that actually tastes just like the store bought kind. The texture is silkier and it’s a little sturdier. Plus, it doesn’t have corn syrup! Yay! It’s actually pretty quick to make and gets used in both the filling and frosting of this cake. So, for me, it was worth it to spend 20 minutes making the marshmallow. However, I’ve made this cake plenty of times with the store bought kind (we always get Kraft Jet-Puffed), and it’s great. So, whatever you feel up for is fine!

How to make chocolate s’mores cake

Make the chocolate cake layers. Sift and whisk the dry ingredients.

Whisk the wet ingredients, sans coffee.

Slowly whisk in the coffee to the wet ingredients, whisking quickly.

Slowly add the wet ingredients to the dry, then mix for exactly 2 minutes. Divide between cake pans and bake.

Make the graham crust, press into a pan, and freeze.

Make the marshmallow fluff (if using homemade).

Use half of the fluff to make the chocolate marshmallow buttercream.

Make the chocolate ganache drip.

Assemble the layers.

Then frost (and decorate as desired).

Enjoy!

Tips and notes for this recipe

Split up your work!

You can easily split things up to save time/sanity. Any of the components of this cake can be made ahead, just be sure to store them correctly. The cake layers should be double wrapped in plastic and frozen (weird, but it stays fresher). The ganache should be refrigerated and can be reheated in the microwave in 10 second intervals or by putting in a glass of hot water. The graham crust can just be left in the freezer until you’re ready to assemble, but cover with plastic wrap if they’ll be in there more than a few hours. The frosting should be covered and refrigerated, then brought to room temperature and stirred a little. The weird one is the fluff. You technically can leave it at room temperature, tightly sealed, for up to two weeks. I haven’t tried that long, but I do know it lasts at least a few days on the counter perfectly fine!

Refrigerate after frosting

If you use the frosting right after making it, you’ll likely need to refrigerate it for just a bit to set it. Once it’s set, you’re fine to leave it out. But you do need that initial chilling to help bring all of the frosting components together solidly.

Adjust the buttercream based on climate

If this cake will be outside or in the sun or if you live in a very humid or warm area, you’ll want to use little to no heavy cream in the chocolate marshmallow buttercream. Essentially, use just a splash if your chocolate isn’t melting smoothly or if you haven’t melted chocolate for baking very many times (it can feel tricky at first). This will help create a thicker, sturdier frosting that can stand up to heat or humidity.

Don’t overdo it with the marshmallow filling

Since marshmallow fluff—homemade or store bought—is on the thin side, you don’t want a thick layer of it as your filling. I like to do a thin layer of chocolate marshmallow buttercream followed by a thin layer of fluff. Together, it’s a little sturdier and leaves room for the graham crumble and ganache. If you’re a big frosting fan, cut each layer of cake in half to get more of it in there—but still do thin layers so the cake doesn’t start sliding around.

You might also like:

Gooey S’mores Cookies

Black & White Oreo Cupcakes (with marshmallow buttercream!)

Hot Cocoa Cake

Double Chocolate Cupcakes

20 Minute, No-Bake Chocolate Cream Pie

Chocolate S’mores Cake

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prep time: 1 hour, 30 minutes
bake time: 25-30 minutes
total time: 2 hours (includes assembly time; can be broken up)

servings: 12-16

Ingredients:

for the chocolate cake layers

1 ⅔ cups (335g) granulated sugar
1 ⅔ cups (226g) flour, sifted
¾ cup (75g) unsweetened cocoa powder, sifted
2 teaspoons (8g) baking powder
1 teaspoon (5g) baking soda
½ teaspoon (3g) sea salt
2 eggs, room temperature
1 cup (236g) buttermilk, room temperature*
½ cup (108g) avocado oil (can sub vegetable or canola oil)
1 tablespoon (13g) pure vanilla extract
1 cup (240g) hot, light roast coffee (or hot water)

for the graham cracker crust crumbles

4 full graham crackers
2 tablespoons butter, melted

one batch marshmallow fluff (or two 7oz jars store bought fluff/cream)

one batch chocolate marshmallow buttercream

see recipe notes for adjusting to your climate

for the chocolate ganache drizzle (this makes more than you’ll need--you can halve it or chill the extras)

4 ounces semi-sweet or dark chocolate chips (or baking chocolate, chopped)
3 ounces heavy whipping cream

Instructions:

make the chocolate cake layers

Preheat your oven to 325. Lightly grease and flour two 8” to 9” cake pans (or use baking spray) and line the bottom with parchment paper or silicone baking mats. This is also a great time to set your coffee to percolate (unless using hot water or espresso and hot water, which is what I do).
Whisk together the sugar, flour, cocoa powder, baking powder, baking soda, and salt in the bowl of your stand mixer or a large mixing bowl, sifting everything but the sugar (unless yours is fine enough to sift--go for it!). Set aside.
In a separate medium mixing bowl, whisk the eggs, buttermilk, oil, and vanilla together until well-blended and fully emulsified, about 1 minute.
Very, very slowly stream the hot coffee or water into the wet ingredients, whisking vigorously and constantly as you pour to avoid scrambling the eggs. Feel free to do this in segments if it’s easier. If you do scramble some of the eggs, you can run the mixture through your fine mesh sieve to remove the cooked egg bits.
Using the paddle attachment, turn your stand mixer to low (or use a hand mixer) and slowly pour the wet ingredients into the dry. This should take about 30 seconds or so. The batter will clump up then thin out. Once you’ve poured all the wet ingredients, immediately turn off the mixer. Scrape down the bottom and sides. Beat on medium for exactly 2 minutes (set a timer).
Evenly divide batter between prepared pans. Bake for 25-30 minutes, until a toothpick inserted in the middle of each cake comes out with just a few moist crumbs (ideally not fully clean, as this could mean they’re over baked). Check early and rotate halfway if not using convection.
Let cool 5-10 minutes in the pans then remove to a cooling rack to cool completely.

make the graham cracker crust crumble

While the cakes bake, make the graham cracker crumble. In a small food processor or blender, grind the graham crackers until a sandy texture. Add melted butter and pulse a few times until blended.
Pour out mixture onto a parchment lined baking sheet or small baking pan. Press down in a thin-ish layer about 8” x 8” or so. You’re just looking to create something that can be broken up for the filling, so no need for perfection here.
Freeze the pan until ready to use. If making ahead, cover with plastic wrap so the grahams don’t become stale or absorb the smells of your freezer (doesn’t matter how clean your freezer is--this is just a reality of freezers).

make the marshmallow fluff and chocolate marshmallow buttercream

While the cakes cool, make the marshmallow fluff and chocolate marshmallow buttercream. (You can make these ahead of time. If you do, tightly cover both. The buttercream should be refrigerated but the marshmallow should actually stay at room temperature (it’s shelf-stable for up to 2 weeks). The day you’ll assemble the cake, let the buttercream come to room temperature for a few hours then give it a good stir or even whip it briefly to smooth it out.)

make the chocolate ganache drizzle

Combine the chocolate and heavy cream in a heatproof bowl. Bring 1-2” water to a boil in a small to medium saucepan that can hold the bowl on top in such a way that all or almost all of the ingredients are over the water and not over the stove.
Once the water boils, turn down the heat to medium low or low and place the bowl over it. You want it to stay simmering without getting too hot. Stir constantly with a rubber spatula until the chocolate is mostly melted. Remove from heat and stir or whisk vigorously until it is all melted and smooth. Return to heat if some chunks remain, but don’t worry if the color looks a little streaky (usually only noticeable in a glass bowl). It’s best not to overheat the chocolate because it will become grainy and separated. Note: some brands of chocolate will look like they’re seizing up (i.e. a clumpy mess) right before they smooth out and melt completely. Just keep stirring and keep the heat low and the ganache should come together.
Set aside or place in a drip bottle to cool slightly, about 20 minutes. You can also make this ahead of time and keep refrigerated. About 10 minutes before you’re ready to assemble the cake, place the drip bottle in a glass of hot (just below boiling) water or microwave in 10 second intervals until smooth and drizzle-able.

assemble cake

When the cake is cooled, cut off any domed tops (save them to eat with the leftover frosting!). If desired, cut cake layers in half.
Place first layer of cake, cut side up, on your cake plate/board. Spread a thin layer of chocolate marshmallow buttercream on it, followed by a thin layer of marshmallow fluff. If using jarred marshmallow, you may need to stir it a bit to make it spread-able.
Crumble some of the frozen graham cracker crust across the fluff. You can use as much or as little as you’d like, but just be sure to save enough for the remaining layer(s) and any topping, as desired.
Drizzle some of the slightly cooled ganache drizzle over the graham crumble. Don’t use if it’s still hot to the touch, as this will melt the filling.
Follow with the next layer of cake, this time cut side down. Repeat the filling layers until all cake layers are assembled. Aim for the last layer of cake to be cut side down and bottom-of-the-pan side up (really only matters if you cut your cakes in half) as this is the easiest part to frost.
Frost the entire cake in a thin crumb coat of marshmallow buttercream. Chill at least 20 minutes. Frost to desired thickness. Add any remaining marshmallow, graham crumbles, and/or ganache drizzle in desired design.

Enjoy!

Cake should be stored in a truly airtight container. If you have any leftovers, place a piece of plastic wrap right against the cut sides to seal it.