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S'mores Cake Recipe with Graham Cracker Crust and Marshmallow Frosting

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.
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Prep Time 40 minutes
Cook Time 35 minutes
Total Time 2 minutes
Servings: 12 servings
Ingredients Method Notes

Ingredients
  

Chocolate Cake
  • 2 cups All-purpose flour
  • 2 cups Granulated sugar
  • 3/4 cup Unsweetened natural cocoa powder
  • 2 teaspoons Baking soda
  • 1 teaspoon Baking powder
  • 1 teaspoon Fine salt
  • 2 Large eggs
  • 1 cup Buttermilk
  • 1/2 cup Neutral vegetable oil
  • 2 teaspoons Vanilla extract
  • 1 cup Hot water or hot brewed coffee
Graham-Cracker Base and Topping
  • 1 1/2 cups Finely crushed graham-cracker crumbs
  • 5 tablespoons Unsalted butter, melted
  • 2 tablespoons Light brown sugar
  • 1/4 teaspoon Salt
  • 1/2 cup Additional graham-cracker crumbs
Marshmallow Buttercream
  • 1 cup Unsalted butter, softened
  • 1 7-ounce jar Marshmallow creme or marshmallow fluff
  • 1 1/2 cups Confectioners' sugar
  • 1 teaspoon Vanilla extract
  • 1/4 teaspoon Salt
  • 1-2 tablespoons Heavy cream or milk, if needed
Chocolate Ganache
  • 4 ounces Semisweet or bittersweet chocolate, finely chopped
  • 1/2 cup Heavy cream
Optional Decoration
  • As desired Miniature marshmallows
  • As desired Broken graham-cracker pieces
  • As desired Chocolate-bar squares or chocolate shavings

Method
 

Step-by-Step
  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. 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.
  10. 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.