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This S’mores Cake is an over the top decadent dessert with layers of moist chocolate cake, graham cracker crust, chocolate ganache, and homemade marshmallow filling, all surrounded by a luscious buttercream frosting. It’s a scrumptious, irresistible twist on one of summer’s most iconic desserts!
Don’t s’mores just make you feel like a kid again? I think that’s why we all love them so much! Some of our other favorite s’mores desserts are my much-loved S’mores Bars, the easy and munchable S’mores Snack Mix, S’mores Dip, handheld S’mores Cupcakes, and Chocolate Chip S’mores Cookies.
Decadent Chocolate S’mores Cake
It took me quite a few tries to find a s’mores cake that I loved. There were a couple of other iterations of this recipe that got only “meh” reactions, including one with a graham cracker cake instead of a chocolate one that I had high hopes for but that just didn’t deliver when it came to s’mores flavor.
My s’mores cupcake has graham cracker frosting that I’m kind of obsessed with, so my next thought was to go that direction. But again, it just wasn’t quite what I wanted in a tall layer cake that would be good for celebrations.
It wasn’t until I finally tried a thick layer of graham cracker crust as a base for the chocolate layers that things started to really come together. You can actually taste the graham cracker and there is a crunchy texture that stands up to the other elements of the cake.
The toasted marshmallow buttercream is made with marshmallows that you actually toast under the broiled until they are golden brown, then add them right to a classic butter and powdered sugar buttercream base. It’s crazy good and adds that toasty, almost burnt sugar flavor that I love about the original campfire s’mores.
There is even a layer of homemade marshmallow fluff that I toasted with my kitchen torch. I fully anticipated this being a total vanity move and was prepared to tell you it was unnecessary since the cake it still super delicious without it.
But no, it’s absolutely one of my very favorite parts of the over-the-top dessert. So even though it’s a bit of extra work right at the end when you are so close to being done, I encourage you to power through and make the marshmallow fluff. You won’t regret it!
True, there are a few components to this cake and it takes longer to assemble than most of the other dessert recipes on this site, but I promise it’s 1,000 percent worth it. I cut up slices and delivered them to friends who helped with the taste testing and everybody raved about this one.
I love researching cake recipes and definitely pulled inspiration from Life Love and Sugar, Cake By Courtney, and the Preppy Kitchen for my version. They are all such inspiring and creative bakers and if you haven’t checked them out, you really should!
Tips for making s’mores cake
Before we get started, there are a few things to know that will help take away a lot of the stress of making this recipe. None of the elements are very hard to make, but with a recipe like this where there are a number of different components, I want everyone to be successful on their first try! These are my best tips and tricks from an admittedly self-taught baker.
- Whenever I’m doing a major bake like this one, I find it’s always best to read through ALL of the ingredients and instructions first to make sure I have everything I need going into it. I hate to be in the middle of assembling a cake and realize I forgot to make a filling component, or worse yet, have to run to the store for an ingredient I didn’t realize I was running low on (I’m looking at you powdered sugar)!
- Clear out some freezer space. If you want really professional looking results, the trick is utilizing your freezer when assembling the cake layers and decorating. It takes a little time and yes, you are in and out of the freezer, but setting the layers will really help the cake be more firm and easier to assemble and decorate.
It’s amazing how much easier it is to work with cake layers and buttercream frosting when you give them 5-10 minutes to set in the freezer before moving on to the next step.
- Use cardboard cake rounds or acrylic cake discs for easier assembly and decorating. Once I started buying these inexpensive cardboard bases for my cakes, it made decorating so much easier! They are typically 1/4-inch larger in diameter than the cake pans, which gives you a perfect guide for applying the outer layer of frosting. And they provide much needed stability when transferring the cake in and out of the freezer rather than trying to figure out a way for your entire cake stand to fit. Then once the cake is finished, you can transfer the whole thing to a clean, beautiful cake stand by sliding a cake lifter under the cardboard round and setting the cake onto your cake stand.
- Give yourself time. A big cake like this one can be a nightmare if you try to rush it. I will usually make my cake layers and buttercream a day or more in advance. Both can be frozen for 1-2 months, if needed even. Then on the day I plan to assemble the cake, let them both come up to room temperature. Always transfer the buttercream back into a large bowl and beat it again for a couple of minutes to make sure it is smooth and spreadable before you start working with it.
Let’s make s’mores cake!
- Make the graham cracker crust base for the cake layers: If you have a food processor , just pulverize a bunch of graham crackers into crumbs, then mix in a little sugar and butter. Divide the buttery crumbs evenly between three 8-inch cake pans lined with circles of parchment paper on the bottom and press them down to compact into a base layer for the cakes.
- Make the chocolate cake batter: Mmmm, cake batter. In a large bowl, beat the sugar and oil until light, about 2 minutes. Then add the eggs and vanilla, and beat again. Add the flour, cocoa powder, baking soda, baking powder, and salt, mixing on low speed just until combined. Add the buttermilk and hot water, mixing again and scraping the sides of the bowl until combined. Divide the batter evenly between the three pans, pouring it directly over the graham cracker crumb layer.
- Bake for about 20 minutes until done: A toothpick or other tester inserted into the center of each cake should come out clean with just a few crumbs. Cool completely before assembling the cake. These layers can be wrapped in plastic wrap and frozen for up to 2 months, then thawed before assembling, if needed.
- Make the ganache: This part sounds fancy but if you have made ganache before you already know just how easy this is. Just heat some heavy cream in the microwave until very hot but not boiling (about 60-90 seconds will do it), then pour this over milk chocolate or semi-sweet chocolate chips in a bowl. DO NOT STIR. Let this sit for 4-5 minutes first, THEN stir and it will come together in a silky smooth chocolate ganache that is absolutely delicious!
- Make the toasted marshmallow filling: Set the oven to broil, then scatter some marshmallows on a baking sheet lined with parchment paper. Stick them under the broiler just until the tops are nice and toasty brown. I almost went a little too far with mine – you really have to watch them! Then while the toasted marshmallows cool down a bit, beat butter and powdered sugar together in a bowl until blended, then add the vanilla and turn the mixer speed up to medium-high, beating for 2-3 minutes until creamy and light. Add the toasted marshmallows and marshmallow fluff, then beat again just until combined.
- Make the chocolate buttercream. I have a whole post dedicated to chocolate buttercream if you want more info on the hows and whys of making it. But you will just beat butter and cocoa powder together until smooth, then gradually add in the powdered sugar, vanilla, and a little salt. Add heavy cream (even milk will work in a pinch) and continue to beat until the frosting reaches a nice, smooth, pipeable consistency that you could easily spread but that will still hold its shape.
- The fun part! Assembly time! Level off the cake tops so they are nice and flat. Place the bottom layer on a cake plate or better yet, on a cardboard cake round. Transfer some of the chocolate buttercream to a piping bag fitted with a large round tip and pipe a thick border of frosting around the rim of the cake to create a wall to hold in the other filling so it doesn’t ooze out as the cake is assembled. Pour half of the ganache directly onto the chocolate cake, then stick the cake in the freezer for 5-10 minutes to set the ganache. Once it has had a chance to set a bit, gently spread half of the toasted marshmallow filling on top of the ganache. Repeat with the next layer of cake and remaining ganache and toasted marshmallow filling. Top with the final cake layer. Use some of the chocolate buttercream to create a thin crumb coat around the top and sides of the cake, then stick it in the freezer for 10-15 minutes.
- Frost the outside: Once the crumb coat is set, start applying the chocolate buttercream around the outside with another cardboard cake round or acrylic disc on top so that you have a top and bottom guide that will help you achieve an even 1/4-inch layer of frosting around the sides. Use a scraper to smooth the sides of the cake. It might take a few turns around holding the scraper at an angle against the sides to smooth them out, and you will likely need to fill in spots with additional frosting a time or two until you get a result that you like. Stick the cake in the freezer for 10 minutes to set, then use a thin, sharp knife to cut off the acrylic disc from the top and smooth out the top with a little extra buttercream. Here is a great video tutorial to help you see how to get nice, clean edges using an acrylic disc or cardboard cake board.
- Make the homemade marshmallow fluff: The final component is the marshmallow fluff that is made by whisking egg whites and salt together in a large bowl of a stand mixer fitted with the whisk attachment until frothy. Gradually add 1/3 cup of sugar to the egg whites while whisking, then continue to whisk until soft peaks form. Meanwhile, heat the remaining sugar and corn syrup in a small saucepan over medium-high heat, stirring occasionally, until it reaches 240 degrees F on a candy thermometer . Set the mixer to medium-low speed, then slowly drizzle in the hot sugar mixture into the egg whites in a very thin stream over the course of a minute or two. Increase the mixer speed back to medium-high and whisk another 5-10 minutes or so until thick and the fluff has cooled quite a bit.
- Garnish & finish! We’re almost there! Transfer the marshmallow fluff to a piping bag fitted with a large tip. I like to assemble a couple of actual s’mores using graham cracker halves, broken up Hershey bars, and large marshmallows and arranging them on top of the cake, but you could instead just pipe the marshmallow fluff on top and stick broken up graham crackers and Hershey bar pieces into the top instead. Either way, pipe or spread mounds of marshmallow fluff on top, then use a kitchen torch to gently toast it.
Phew! That’s it! Now you can slice and serve your delicious creation! It’s a big cake and will feed a lot of people. If you have leftovers, I recommend slicing them and freezing individual slices wrapped well in plastic wrap so you can thaw and enjoy as much as you want at a time.
More cake recipes that you’ll love
- Cherry Crisp Cake
- The BEST Red Velvet Cake
- Homemade Funfetti Cake
- San Jose Burnt Almond Cake
- Vintage Cherry Chip Cake
- German Chocolate Cake
- Aunt Becky’s Black Forest Cake
Graham Cracker Crust
- 2 1/2 cups graham cracker crumbs
- 1/3 cup granulated sugar
- 1/2 cup salted butter melted
- 1 cup vegetable or canola oil
- 2 cups granulated sugar
- 3 large eggs
- 2 teaspoons vanilla extract
- 2 all-purpose flour
- 1 cup cocoa powder
- 2 teaspoons baking soda
- 1 teaspoon baking powder
- 1 teaspoon salt
- 1 cup buttermilk room temperature
- 1 cup hot water
- 1 cup milk chocolate or semisweet chocolate chips
- 1/2 cup heavy cream
Toasted Marshmallow Filling
- 24 large marshmallows
- 1 cup salted butter room temperature
- 1 cup powdered sugar
- 1/2 teaspoon vanilla extract
- 1 jar marshmallow fluff
- 2 cups salted butter room temperature
- 1 1/3 cups unsweetened cocoa powder
- 5 cups powdered sugar
- 6 Tablespoons heavy cream
- 2 teaspoons vanilla
- Pinch of salt
- 3 egg whites room temperature
- 1/4 teaspoon salt
- 1 cup sugar divided
- 1/2 cup light corn syrup
- 1 teaspoon vanilla extract
For decoration (optional)
- Additional graham crackers
- Additional Hershey bars broken up
- Additional large marshmallows
- Preheat oven to 350 degrees F. Line three 8-inch baking pans with parchment paper circles and set aside.
Graham Cracker Crust
- Mix graham cracker crumbs, butter, and sugar together in a bowl, then divide evenly between the bottom of each pan. Press down, then bake for 8-10 minutes.
- Beat the oil and sugar in the bowl of a stand mixer on medium speed until creamy and light, about 2 minutes.
- Add the eggs and vanilla, mixing well until combined.
- In a separate bowl, whisk the flour, cocoa powder, baking soda, baking powder and salt. Add the dry ingredients and buttermilk alternately, half at a time, mixing just until combined each time and scraping the sides of the bowl.
- Add the hot water right at the end and mix well. Divide the batter evenly between the pans, pouring it right over the graham cracker crumbs.
- Bake for 25-30 minutes at 350 degrees F until a toothpick inserted into the center of the cakes comes out clean with just a few crumbs clinging to it.
- Cool the cake layers completely and level with a sharp serrated knife.
- Heat the cream in the microwave for 30-60 seconds until hot. Pour over the chocolate chips in a small bowl, then let sit for 5 minutes. Stir until melted and smooth. Let cool while preparing the marshmallow filling.
Toasted Marshmallow Filling
- Set oven to broil with a rack set 2/3 of the way up. Spread the marshmallows in an even layer on a baking sheet lined with parchment paper.
- Toast the marshmallows until they start to brown (watch them closely! This can happen in just a few seconds!), then remove them from the oven and flip. Toast again on the other side. Let them cool for a few minutes.
- Meanwhile, beat butter, powdered sugar, and vanilla in a large mixing bowl until creamy and smooth.
- Add the cooled marshmallows and jar of marshmallow fluff, then beat well until combined.
Chocolate Buttercream Frosting
- In a large bowl, beat the butter and cocoa powder until smooth. Gradually add the powdered sugar, mixing on low speed to combine.
- Add the vanilla, heavy cream, and pinch of salt and beat well for 3-4 minutes until creamy and smooth. The frosting should be a nice, thick consistency that is spreadable but also holds its shape. Add a little more cream, a teaspoon or two at a time, to get it to the desired consistency.
- Use a sturdy spoon or spatula to stir the frosting, pressing it against the sides of the bowl for a few minutes, to knock out some of the air bubbles for a smoother appearance on the sides of the cake.
- Whisk egg whites and salt on medium speed in a mixer until frothy. Add 1/3 cup of the sugar, 1 tablespoon at a time, whisking for 20 seconds between each addition.
- Add 2/3 cup of the sugar to a small saucepan along with the corn syrup. Heat over medium-high heat until it reaches 240 degrees F.
- With mixer running on medium-low speed, very slow pour the hot sugar mixture in a thin stream over 1-2 minutes until it has all been added.
- Whisk on medium-high speed for 5-10 minutes until thickened and cooled.
- Set bottom cake layer, graham cracker crust side down, on a cardboard or acrylic cake disc for easier decorating, or directly onto a cake plate.
- Transfer some of the chocolate buttercream to a piping bag fitted with a wide tip and pipe a thick ring of frosting around the rim of the cake.
- Spread half of the chocolate ganache on top of the cake inside the ring of frosting. Transfer to the freezer for 5 minutes to set the ganache layer.
- Spread half of the toasted marshmallow filling on top of the ganache layer. Gently place the next layer of cake on top of the marshmallow filling, then repeat piping a ring of chocolate buttercream, filling with the remaining ganche, chilling to set, then adding the remaining toasted marshmallow filling.
- Place the final cake layer on top and frost the outside of the cake with a thin crumb coat of chocolate buttercream frosting. Transfer the whole cake to the freezer for 15-30 minutes to set up.
- Remove the cake from the freezer and top with another acrylic cake disc or cardboard cake round. Frost the outside edges of the cake with the chocolate frosting, using a cake scraper to scrape the sides smooth. You may need to fill in holes with additional frosting and repeat the process of dragging the cake scraper around the cake to get a smooth finish. Place the cake back in the freezer for another 10-15 minutes.
- Use a thin, sharp knife to separate the cake disc or board from the top of the cake. Spread the remaining chocolate frosting on top.
- Assemble graham cracker halves, squares of Hershey’s chocolate, and large marshmallows into s’mores and place them on top of the cake, if desired.
- Fill a large piping bag fitted with a large tip with wide teeth with the marshmallow fluff. Pipe the marshmallow fluff all over the top of the cake.
- Use a kitchen torch to toast the marshmallow fluff and marshmallows in the s’mores decorating the top of the cake, then slice and serve.
- Leftover cake can be sliced into individual servings and frozen wrapped in plastic wrap. Thaw at room temperature before serving.