This s’mores cake recipe makes a rich 9-by-13-inch dessert with a fudgy chocolate cake, buttery graham-cracker base, fluffy marshmallow buttercream, and silky chocolate ganache. It serves 12–16 people and takes about 2 hours 15 minutes from preparation through decorating, including the cake’s cooling time.
Every bite brings together the classic campfire combination of chocolate, graham crackers, and marshmallows in a party-ready cake. The soft cocoa crumb contrasts with the crisp graham layer, while the creamy frosting and optional toasted marshmallows give this occasion dessert its irresistible s’mores finish.
This s’mores cake is designed for easy sharing, making it a wonderful choice for birthdays, backyard gatherings, potlucks, holiday tables, and casual celebrations. Since everything bakes in one 9-by-13-inch pan, you get the drama of a decorated layer cake without stacking or trimming multiple rounds.
The texture is the real star. A tender chocolate crumb sits on a lightly crisp graham-cracker base, then gets covered with cloudlike marshmallow buttercream and a thin coat of glossy ganache.
For another fun dessert idea to serve at a party, you can also browse this easy cake balls recipe. It is especially useful when you want a second bite-size treat alongside the larger cake.
Ingredients You’ll Need
The cake batter uses familiar pantry staples: flour, sugar, natural cocoa powder, baking soda, baking powder, salt, eggs, buttermilk, vegetable oil, vanilla, and hot water or coffee. Oil keeps the crumb moist, while buttermilk adds gentle tang and helps balance the sweetness.
The graham base combines 1 1/2 cups finely crushed crumbs with melted butter, light brown sugar, and salt. Reserve the additional 1/2 cup of crumbs for the topping so every serving gets a little graham-cracker flavor on top as well as underneath.
For the frosting, softened butter is whipped with a 7-ounce jar of marshmallow creme, confectioners’ sugar, vanilla, and salt. The ganache needs only 4 ounces of finely chopped semisweet or bittersweet chocolate and 1/2 cup heavy cream.
Use about 10–12 full graham-cracker sheets to make the 1 1/2 cups of base crumbs.
Choose natural, unsweetened cocoa powder rather than a sweetened cocoa mix.
Keep miniature marshmallows, chocolate pieces, and broken graham crackers ready if you want a more decorative finish.
How to Make It Step-by-Step
Step 1: Begin by heating the oven to 350°F and preparing the pan. Grease a 9-by-13-inch baking pan, line it with parchment, and leave a little parchment over the sides for easier handling after cooling.
Step 2: Stir together the graham-cracker crumbs, melted butter, brown sugar, and salt until every crumb looks lightly coated. Press the mixture firmly into an even layer across the pan, then bake for 8 minutes to set the base before cooling it briefly.
Step 3: Whisk the flour, granulated sugar, cocoa powder, baking soda, baking powder, and salt in a large mixing bowl. A thorough whisk helps distribute the leaveners and prevents pockets of cocoa or salt in the finished cake.
Step 4: Add the eggs, buttermilk, oil, and vanilla to the dry mixture. Mix just until combined, then slowly pour in the hot water or hot brewed coffee while mixing; the batter will become very thin, and that is completely normal.
Step 5: Pour the batter gently over the briefly cooled graham base. Bake for 30–35 minutes, checking for a center that springs back lightly and a toothpick that emerges with a few moist crumbs rather than wet batter.
Step 6: Let the cake cool completely in the pan, which usually takes about 1 hour. This waiting period matters because marshmallow buttercream can soften, melt, or slide when spread over a warm cake.
Step 7: Make the frosting while the cake cools or once it is nearly ready. Beat the softened butter until light and creamy, beat in the marshmallow creme, then mix in the confectioners’ sugar, vanilla, and salt; add cream or milk only if the consistency needs adjustment.
Step 8: Prepare the ganache by placing the finely chopped chocolate in a heatproof bowl. Heat the heavy cream until steaming but not boiling, pour it over the chocolate, wait 2 minutes, and stir until smooth and glossy.
Step 9: Allow the ganache to cool until thickened but still pourable. Spread the marshmallow frosting over the cooled cake, then drizzle or gently spread the ganache over the frosting without pressing down too firmly.
Step 10: Scatter the reserved graham crumbs over the ganache and add optional marshmallows, graham pieces, or chocolate-bar squares. If you want toasted marshmallows, brown them briefly with a kitchen torch immediately before serving and keep the flame moving.
For a different fruit-forward dessert on your occasion menu, our raspberry cake recipe offers a bright contrast to this deeply chocolatey bake.
Pro Tips for the Best S’mores Cake
Hot brewed coffee is my preferred liquid for this cake. It intensifies the cocoa flavor without making the cake taste like coffee, but hot water works perfectly when you prefer a coffee-free dessert.
Press the graham base firmly and evenly, especially in the corners. A compact base is easier to slice and gives the soft cake a pleasant crisp layer instead of loose crumbs.
Use room-temperature or properly softened butter for the frosting. If the butter is too cold, the buttercream may look lumpy; if it is melted, the frosting may not hold its shape.
Ganache temperature is equally important. Hot ganache can liquefy the marshmallow buttercream, so let it cool until it flows slowly from a spoon before pouring it over the cake.
For clean slices, chill the decorated cake briefly before cutting, if your schedule allows.
Use a sharp knife and wipe the blade between cuts for tidy squares.
Add toasted marshmallows right before serving rather than several hours ahead.
Keep the optional toppings varied so each piece has chocolate, graham, and marshmallow elements.
Decorating and Serving Ideas
The simplest finish is a smooth layer of marshmallow buttercream, a loose ganache drizzle, and a shower of graham crumbs. For a more eye-catching party cake, arrange miniature marshmallows around the edges, tuck in broken graham pieces, and add chocolate-bar squares at a slight angle.
A kitchen torch creates the closest visual connection to a campfire s’more. Toast only the exposed marshmallows, keep the flame moving, and work carefully; do not put a glass or disposable baking pan under a broiler unless it is specifically broiler-safe.
Cut the cake into 12 generous portions or 16 smaller party squares. Serve it at room temperature so the cake stays tender and the frosting is creamy rather than firm.
If you enjoy cakes with a marbled chocolate presentation, you may also like this swirled marble cake for another celebration-friendly option.
Storage and Make-Ahead Advice
Store the frosted cake covered in the refrigerator if you are making it ahead, especially because the marshmallow buttercream and ganache are soft. Let it sit at room temperature before serving so the chocolate cake and frosting are not overly firm.
For the best appearance, add toasted marshmallows immediately before serving. They can become sticky and lose their shape during storage, even when the cake itself remains delicious.
The undecorated cake can be cooled completely, covered, and held while you prepare the frosting and ganache. If you need to transport the dessert, keep it level and chilled, then add delicate graham pieces or toasted marshmallows after arrival.
S'mores Cake Recipe
A moist chocolate cake baked over a buttery graham-cracker base, finished with marshmallow buttercream, chocolate ganache, graham crumbs, and optional toasted marshmallows. This 9-by-13-inch dessert serves 12–16.
17-ounce jarMarshmallow creme or marshmallow fluff
1 1/2cupsConfectioners' sugar
1teaspoonVanilla extract
1/4teaspoonSalt
1-2tablespoonsHeavy cream or milk, if needed
Chocolate Ganache
4ouncesSemisweet or bittersweet chocolate, finely chopped
1/2cupHeavy cream
Optional Decoration
As desiredMiniature marshmallows
As desiredBroken graham-cracker pieces
As desiredChocolate-bar squares or chocolate shavings
Method
Step-by-Step
Heat the oven to 350°F. Grease and line a 9-by-13-inch baking pan with parchment, leaving enough overhang to help lift the cooled cake if desired.
Mix 1 1/2 cups graham-cracker crumbs with the melted butter, brown sugar, and 1/4 teaspoon salt. Press the mixture firmly over the bottom of the prepared pan, bake for 8 minutes, and cool briefly.
Whisk the flour, granulated sugar, cocoa powder, baking soda, baking powder, and 1 teaspoon salt in a large bowl. Break up any cocoa lumps so the finished cake has an even texture.
Add the eggs, buttermilk, oil, and vanilla to the dry ingredients and mix until combined. Slowly pour in the hot water or hot brewed coffee while mixing until the batter is smooth and thin.
Pour the chocolate batter over the baked graham-cracker base. Bake for 30–35 minutes, until the center springs back lightly and a toothpick comes out with a few moist crumbs.
Cool the cake completely in the pan, allowing about 1 hour for thorough cooling. Do not frost a warm cake because the heat can melt the marshmallow buttercream.
Beat the softened butter until light and creamy. Beat in the marshmallow creme, then add the confectioners' sugar, vanilla, and salt; add 1–2 tablespoons cream or milk only if the frosting needs loosening.
Place the chopped chocolate in a heatproof bowl and heat the heavy cream until steaming but not boiling. Pour the cream over the chocolate, let it stand for 2 minutes, and stir until smooth.
Cool the ganache until thickened but still pourable. Spread the marshmallow frosting over the completely cooled cake, then drizzle or spread the ganache across the top.
Finish with the remaining graham-cracker crumbs and any miniature marshmallows, broken graham-cracker pieces, or chocolate-bar squares. For a toasted finish, briefly brown the marshmallows with a kitchen torch immediately before serving.
Notes
Use hot brewed coffee instead of water for a deeper cocoa flavor without a noticeable coffee taste. Cool the ganache before applying it so it does not liquefy the frosting. Toast marshmallow decorations just before serving because they become sticky during storage. Never place a glass or disposable baking pan under a broiler unless it is specifically broiler-safe.
Final Thoughts
This s’mores cake recipe turns a beloved campfire treat into a generous celebration dessert that is easy to bake, decorate, and share. The graham-cracker base gives the cake structure, the chocolate crumb keeps every forkful soft, and the marshmallow buttercream and ganache create the familiar s’mores flavor in a polished form.
For the most tempting finish, wait until the cake is completely cool before frosting, let the ganache thicken before drizzling, and toast the marshmallows just before serving. Set out a sharp knife, cut the cake into squares, and expect these chocolatey, graham-studded slices to disappear quickly.
