Ultimate S’mores Cake

Jun 09

Layers of graham cracker crust, chocolate cake, chocolate ganache, toasted marshmallow filling, chocolate frosting and marshmallow fluff truly make this the ultimate s’mores cake!
This post is a long time coming! I’ve diligently been testing different s’mores cake recipes for years now. Seriously! It’s been a personal mission of mine to find (what I consider) the best one. The first s’mores cake I made was Sweetapolita’s original Campfire Delight Cake, made up of dark chocolate cake layers, toasted marshmallow filling and malted chocolate frosting. To this day, it’s one of my favorite cakes, but it didn’t have a graham cracker element to it which I felt was crucial to a s’mores cake. (In her new cookbook, “Sweetapolita Bakebook,” she made some revisions and the new recipe has graham cracker crumbs!)
Throughout the last couple years, I’ve tried several other s’mores cake recipes, some with chocolate cake layers and some with graham cracker cake layers. With the graham cracker cake layers, I always hope for the true graham cracker flavor to come out, but I’ve always been disappointed. So, I lean toward the chocolate cake layers as my base, and after making my sister a peanut butter s’mores cake for her birthday a couple years a couple years ago, I discovered that baking my chocolate cake on a graham cracker crust was my favorite way of incorporating the graham cracker flavor into a s’mores cake. You get a nice crunch in each bite, like you would with a real s’more.
Since I hadn’t found a single s’mores cake that rocked my world the way I had hope, I decided I would create my own, using some of my favorite elements from the cakes I had tried. One of these components was the Toasted Marshmallow Frosting from Sweetapolita’s Campfire Delight Cake. You guys! It’s unreal! You broil marshmallows in your oven until they’re golden brown, and then, once they’ve had a few minutes to cool, you add the toasted marshmallows to butter, powdered sugar and marshmallow cream. Unreal, right? I also decided to add a thin layer of chocolate ganache under the toasted marshmallow filling to give the cake even more resemblance to a real s’more. I topped it off with chocolate frosting and homemade toasted marshmallow fluff.
So, in case I lost you, here’s how the cake stacks up: toasted graham cracker crust, dark chocolate cake layers, chocolate ganache, toasted marshmallow filling, chocolate frosting and marshmallow fluff. Is your mouth watering yet? I hope so!
I haven’t cut into the cake yet (it’s for my cute cousin’s birthday this weekend), but I assure you, I layered all the scraps and leftovers to create a sample-size version of the cake (for quality control purposes) and I’m so excited with how it all turned out! It’s exactly what I wanted from a s’mores cake! I definitely want you to see all the goodness inside, so I’ll add those pictures after the weekend. I just couldn’t wait any longer to share this recipe with you.
All the ingredients and instructions are below. This cake definitely has a few more steps than your ordinary cake, but this cake isn’t just any ol’ cake. It’s the Ultimate S’mores Cake. Just give yourself enough time to make all the elements or spread it out over a couple days. And make sure to watch my quick time-lapse video to see how I assembled it all.

Ultimate S'mores Cake

Yield 1 3-layer, 8-inch cake

Layers of graham cracker crust, chocolate cake, chocolate ganache, toasted marshmallow filling, chocolate frosting and marshmallow fluff truly make this the ultimate s'mores cake!


For the Graham Cracker Crust

  • 3 cups graham cracker crumbs, about 25-27 rectangular crackers (this is best done in a food processor or blender, but can be done by placing the graham crackers in a zip-lock bag and rolling over the crackers with a rolling pin)
  • 3/4 cup unsalted butter, melted
  • 1/2 cup granulated sugar 

For the Chocolate Cake

  • 1 3/4 cups, plus 2 tablespoons all-purpose flour
  • 2 cups, minus 2 tablespoons granulated sugar
  • 3/4 cups good cocoa powder
  • 2 teaspoons baking soda
  • 3/4 teaspoon baking powder
  • 1 teaspoon kosher salt
  • 1 cup buttermilk, shaken
  • 1/2 cup vegetable oil
  • 3 large eggs, at room temperature
  • 1 teaspoon pure vanilla extract
  • 1 cup hot water 

For the Toasted Marshmallow Filling (recipe source: Sweetapolita, Campfire Delight Cake)

  • 16 large white marshmallows
  • 1 cup powdered sugar, sifted
  • 1 cup (2 sticks) unsalted butter, room temperature
  • 1/2 teaspoon pure vanilla extract
  • 1 jar (about 200 g) marshmallow fluff

For the Chocolate Ganache

  • 1 cup semi-sweet or dark chocolate chips
  • 1/2 cup whipping cream 

For the Chocolate Frosting (adapted from Sweetapolita)

  • 2 cups unsalted butter, room temperature
  • 5 cups powdered sugar, sifted
  • 1 tablespoon pure vanilla extract
  • Pinch of salt
  • 10 oz. good quality chocolate (I use semi-sweet or dark chocolate), chopped, melted and cooled
  • 1/2 cup heavy whipping cream 

For the Marshmallow Fluff (recipe source: HeatherChristo.com)

  • 3 egg whites, room temperature
  • 1/4 teaspoon salt
  • 1/3 cup sugar
  • 1 cup light karo syrup
  • 2 tablespoons water
  • 1 tablespoon vanilla bean paste or clear vanilla extract


For the Graham Cracker Crust

  1. Preheat your oven to 375 degrees F. Spray three 8-inch round cake pans with non-stick spray and then line with parchment. Spray again. Set aside.
  2. In a medium sized bowl combine the graham cracker crumbs, melted butter and sugar. Stir until all the graham cracker crumbs are damped by the melted butter.
  3. Divide evenly between the three pans and press down firmly with your hand or the back of a spoon.
  4. Bake for 8-10 minutes, until golden brown. Let cool while you make the chocolate cake batter. 

For the Chocolate Cake

  1. Preheat the oven to 360 degrees F.
  2. Combine the flour, sugar, cocoa, baking soda, baking powder, and salt into the bowl of an electric mixer fitted with a paddle attachment and mix on low speed until combined.
  3. In another bowl, combine the buttermilk, oil, eggs, water and vanilla.
  4. With the mixer on low speed, slowly add the wet ingredients to the dry, scraping the bottom of the bowl with a rubber spatula.
  5. Pour the batter into the prepared pans (about 12 ounces in each pan), over the cooked graham cracker crusts and bake for 18-20 minutes, until a toothpick inserted in the center of the cake comes out almost clean.
  6. Cool in the pans for 10 minutes, then turn them out onto a cooling rack and cool completely.
  7. Wrap in plastic wrap and chill until ready to use. 

For the Toasted Marshmallow Filling

  1. Place the marshmallows on a cookie sheet lined with parchment paper and sprayed with nonstick cooking spray. Place on the middle rack of the oven, and broil the marshmallows until golden brown on top, about 30-60 seconds. Keep your eye on them!
  2. Remove the pan from the oven and gently turn the marshmallows over and broil them again until they are golden brown on the other side.
  3. In the bowl of a stand mixer fitted with the paddle attachment, combine the butter and powdered sugar and beat on low until blended. Add the vanilla and mix on medium speed for about three minutes
  4. With the mixer on low speed, add the marshmallow cream and (cooled) toasted marshmallows, and mix for about one minute. 

For the Chocolate Ganache

  1. In a microwave safe bowl, pour the cream over the chocolate chips and heat for about 45-60 seconds. Stir, and if needed, heat for another 30 seconds to melt the chocolate chips completely. Let cool to room temperature before using.For the Chocolate Frosting1. In a stand mixer fitted with the paddle attachment, beat the butter on medium speed for one minute.
  2. Gradually add the powdered sugar.
  3. Add the vanilla and salt and beat until combined.
  4. Slowly add the cooled, melted chocolate, while the mixer is on medium-low speed. Once all the chocolate is added, stop the mixer and scrape down the sides of the bowl. Turn the mixer on medium-low speed again and mix for another 30 seconds.
  5. Slowly add the whipping cream and continue to beat for 2 more minutes, until light and fluffy.
  6. Using a wooden spoon, mix the frosting by hand, trying to push out any air bubbles. 

For the Marshmallow Fluff

  1. In the bowl of a standing mixer, whisk the eggs and salt until fluffy and frothy.
  2. Meanwhile, heat the sugar, corn syrup, water and vanilla paste. Heat over medium flame until the sugar is dissolved and just simmering, about 5 minutes.
  3. With the mixer on medium speed, add a tiny bit of the hot sugar mixture to the egg whites at a time. (Temper the eggs - don't scramble the them)
  4. Eventually, all of the sugar will be added and then turn the mixer up to high. Beat the mixture on high for about 5 minutes or until very stiff and shiny. 

For the Chocolate Frosting

  1. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter until smooth and light in color, about 2 minutes.
  2. With the mixer on low speed, gradually stream in the cooled, melted chocolate. Scrape down the sides of the bowl and mix for another minute.
  3. Gradually add the powdered sugar, one cup at a time, followed by the salt and vanilla.
  4. Add the heavy cream and then turn the mixer to medium-high speed and beat for 5 minutes.
  5. Frosting can be store in an airtight container in the refrigerator for a week.
  6. When you're ready to frost the cake, bring the frosting back to room temperature and mix by hand with a wooden spoon to push out all of the air pockets. 


  1. Level each chocolate cake layer, and then place the first cake layer, graham cracker side down, on a cake board.
  2. Spread half of the chocolate ganache on the cake layer and then refrigerate or freeze for 10-15 minutes to set the ganache a little.
  3. Carefully spread half of the toasted marshmallow filling over the chocolate ganache and repeat step 2 and 3 for the second cake layer.
  4. Place the final cake layer, graham cracker side down, on top and cover with a crumb coat layer of the chocolate frosting. Refrigerate for 15 minutes to set the crumb coat.
  5. Finish frosting the cake with the chocolate frosting and then decorate the top of the cake with the marshmallow fluff, toasting with a kitchen torch, if desired.

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