Last summer, Emily came back from a sleepover bouncing off the walls about s'mores by the fire pit. The next morning, she looked at me with those big eyes and said, "Mom, can we put s'mores in a cake?"
Challenge accepted.
After three slightly disastrous attempts (one involved marshmallow fluff on the ceiling… don't ask), I finally created this s'mores cake that made Emily declare me "the best mom in the universe." High praise from a kid who once ranked me below our cat.
This isn't just any chocolate cake with marshmallows slapped on top. We're talking a real graham cracker crust baked right into each layer, the moistest chocolate cake you'll ever taste, fluffy marshmallow buttercream, and a glossy milk chocolate drip. Then? Toasted marshmallows on top, because we're not playing around here.
If you love over-the-top desserts that wow a crowd, you'll also want to try my Pumpkin Cheesecake once the weather cools down. But for now, let's talk cake.
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Why You'll Love This S'mores Cake
Honestly? This cake is everything I want a dessert to be. Here's why you'll keep coming back to it:
- Real campfire flavor without needing a fire pit or burning your fingers
- Three layers of texture — crunchy graham crust, soft chocolate cake, fluffy frosting
- Make-ahead friendly — you can split the work over two or three days
- Crowd-pleaser for birthdays, summer parties, or 4th of July
- No fancy skills needed — if you can stir batter, you can make this
- Uses pantry staples like cocoa powder, flour, and sugar
Plus, the toasted marshmallow topping is the kind of thing that makes people pull out their phones the second you set the cake down. Just saying.
Ingredients for This Homemade S'mores Cake
Here's what you'll need. I broke it into sections so it's easier to shop and prep.
the Graham Cracker Crust:
- 18 full sheets (279 grams) graham crackers
- 8 tablespoons (113 grams) unsalted butter, melted
- ½ cup (99 grams) granulated sugar
the Chocolate Cake:
- 2 ¾ cups (330 grams) all-purpose flour
- 3 cups (594 grams) granulated sugar
- 1 cup (84 grams) natural unsweetened cocoa powder
- 1 tablespoon baking soda
- 1 ½ teaspoon baking powder
- 1 ½ teaspoon salt
- 3 large eggs, room temperature
- 1 ½ cups (340.5 grams) buttermilk
- 1 ½ cups (340.5 grams) hot coffee
- ¾ cup (148.5 grams) vegetable oil
- 1 ½ tablespoons vanilla extract
the Marshmallow Fluff Buttercream:
- 1 ½ cups (339 grams) unsalted butter
- 7 cups (794.5 grams) confectioners' sugar
- 10 ounces (283.5 grams) marshmallow fluff
- 2 teaspoons vanilla extract
- ½ teaspoon salt
For the Milk Chocolate Ganache:
- 7 ounces (200 grams) chopped milk chocolate
- ¾ cup (170.3 grams) heavy cream
- pinch of salt
For Decorating:
- miniature marshmallows
- additional graham crackers
- squares of milk chocolate
A quick note: don't skip the hot coffee. You can't taste it, but it makes the chocolate flavor SO much deeper. I learned that one the hard way when I subbed it for water once and Emily said, "It tastes… fine?" Fine is not the goal, friends.
How to Make This Three Layer S'mores Cake
This recipe has a few steps, so I split it into clear sections. Trust me, it's not as scary as it looks.
Prep Your Pans and Oven
- Preheat the oven to 350°F.
- Grease and flour three 8-inch round cake pans (or use nonstick baking spray).
- Line the bottoms with parchment paper.
- Spray or grease the parchment too. Yes, do both. I've had cakes refuse to release before, and it's not pretty.
Make the Graham Cracker Crust
- Crush the graham crackers into fine crumbs in a food processor (or smash them in a zip bag with a rolling pin — Emily's job).
- In a big bowl, mix the crumbs with melted butter and sugar until no dry spots remain.
- Divide the mixture between the three pans.
- Press it firmly into an even layer using a measuring cup or the back of a spoon.
- Bake for 10 minutes, then set aside to cool while you make the batter.
Make the Chocolate Cake Batter
- In a large mixing bowl, whisk together the flour, sugar, cocoa powder, baking soda, baking powder, and salt.
- In a separate bowl, whisk together the eggs, buttermilk, hot coffee, oil, and vanilla extract.
- Pour the wet ingredients into the dry ingredients.
- Mix on low speed for about 2 minutes until just combined.
The batter will be really thin — almost like chocolate milk. That's exactly right! Don't add more flour. I know it's tempting. Don't do it.
Bake the Cake Layers
- Divide the batter evenly between the three prepared pans (right on top of the cooled graham crust).
- Bake for 35 minutes, or until a toothpick comes out with a few moist crumbs.
- Cool the cakes in their pans for 20 minutes.
- Carefully turn them out onto cooling racks to cool completely.
Patience here, please. Frosting a warm cake is how I ended up with that ceiling situation I mentioned.
Make the Marshmallow Fluff Buttercream
- Beat the butter on low speed until smooth and creamy.
- Slowly add the powdered sugar, one cup at a time.
- Mix in the marshmallow fluff, vanilla, and salt.
- Beat on medium-high for 4 full minutes until light and fluffy.
If your kitchen is warm and the buttercream gets too soft, pop it in the fridge for 5–10 minutes. It firms right back up.
Assemble the S'mores Layer Cake
- Level the cakes with a serrated knife if they domed up.
- Place one layer (graham side down) on your cake plate.
- Spread ¾ cup of buttercream on top.
- Repeat with the second layer.
- Set the final layer face down on top.
- Frost the sides and top of the whole cake.
- Refrigerate for at least 30 minutes to set the frosting.
Pour the Chocolate Ganache
- Heat the heavy cream in the microwave at 50% power in 30-second bursts (or on the stovetop) until it just starts to bubble.
- Pour the hot cream over the chopped chocolate and pinch of salt in a glass bowl.
- Let it sit for 2 minutes — don't stir yet!
- Whisk from the center outward until the ganache is smooth and glossy.
- Let it cool 10–15 minutes until thick but still pourable.
- Pipe ganache around the edge so it drips down, then pour the rest in the middle.
Decorate Like a Pro
- Press graham crackers around the bottom of the cake.
- Pile mini marshmallows on top.
- Toast the marshmallows with a kitchen torch until golden (or pop the cake under a broiler for 30–60 seconds — watch it like a hawk!).
- Press extra graham cracker squares and chocolate pieces into the warm, gooey marshmallows.
Storage and Reheating Tips
Got leftovers? Lucky you.
Store the cake in an airtight container in the fridge for up to 4 days. Let slices sit at room temp for 20–30 minutes before serving so the buttercream softens up.
Want to make it ahead? Bake the cake layers up to 2 days in advance and wrap them tightly at room temperature, or freeze for up to 2 months. Assemble the day before, but save the toasted marshmallow topping for right before serving.
Tips and Variations for the Best S'mores Cake
A few things I've learned after making this cake more times than I can count:
- Weigh your flour with a kitchen scale. Scooping with a measuring cup packs in extra flour and dries out the cake.
- Use room temperature eggs and buttermilk so they mix in evenly.
- Want a smaller version? Cut everything in half and use 6-inch pans.
- No buttermilk? Mix 1 cup of milk with 1 teaspoon lemon juice or vinegar and let it sit for 5 minutes.
- For perfectly flat cake layers, use Bake Even strips around your pans.
Tried doubling the ganache once because… more chocolate, right? Wrong. It puddled everywhere. Stick to the recipe on this one!
FAQs About This S'mores Cake Recipe
Yes! Bake the cake layers up to 2 days ahead and store them tightly wrapped at room temperature, or freeze for up to 2 months. Assemble and frost the cake a day before serving, but add the toasted marshmallow topping and graham cracker decorations just before serving for the freshest look and texture.
Store leftovers in an airtight container in the refrigerator for up to 4 days. Let slices sit at room temperature for 20–30 minutes before serving so the buttercream softens and the cake tastes its best. Note that toasted marshmallows on top will soften over time.
Absolutely. Place the cake under your oven broiler on the lowest rack for 30–60 seconds, watching constantly to prevent burning. Alternatively, you can use a long-handled lighter to carefully toast each marshmallow individually.
The most common culprits are overmixing the batter, overbaking, or measuring flour incorrectly. For best results, weigh your ingredients with a kitchen scale, mix only until just combined, and remove the cakes from the oven as soon as a toothpick comes out with a few moist crumbs.
Recipes You May Like
If you loved this s'mores cake, you'll want to bookmark these too:
- Fudgy S'mores Brownies — All the s'mores vibes in handheld form, perfect for picnics.
- Chocolate Molten Lava Cakes — When you want pure chocolate drama on a plate.
- 4th of July Poke Cake — Another showstopper for summer parties.
Final Thoughts on This S'mores Cake
Honestly? This three layer s'mores cake is hands down one of my favorite desserts to make for special occasions. It's got everything — that toasty marshmallow flavor, rich chocolate cake, buttery graham crust, and a serious wow factor when you bring it to the table.
Emily still tells everyone I "invented" it. I'm not correcting her.
Give it a try this weekend, snap a photo, and don't forget to save it to Pinterest so you can find it again. Tag me if you make it — I genuinely love seeing your bakes!
Happy baking,
Three Layer S'mores Cake
Ingredients
Equipment
Method
- Preheat the oven to 350 °F. Grease and flour (or spray with nonstick baking spray) three 8-inch round cake pans. Line the pans with parchment paper, then spray or grease and flour again.
- Make the graham cracker crust. Crush graham crackers into fine crumbs using a food processor or by hand. Combine graham crackers, melted butter, and sugar in a large bowl and mix until no dry clumps remain. Divide the mixture between the three prepared cake pans and press mixture into an even layer using a sturdy measuring cup, glass, or the back of a spoon. Bake for 10 minutes, then set aside to cool.
- Make the cake batter. Using a mixer, combine together the flour, sugar, cocoa powder, baking soda, baking powder, and salt in a large bowl. In a separate smaller bowl, whisk together the eggs, buttermilk, coffee, oil, and vanilla extract. Add the wet ingredients to the dry ingredients and mix on low speed until combined, about 2 minutes. The batter will be thin.
- Bake the cake batter. Divide the batter evenly among the three pans. Bake for 35 minutes, or until a toothpick inserted into the center of the cake comes out with a moist crumb. Cool the cakes in the pan for 20 minutes, then carefully turn out onto cooling racks to cool completely before frosting.
- Make the frosting. To make the frosting, cream the butter until smooth using an electric mixer on low speed. Slowly add in the powdered sugar, 1 cup at a time, followed by the marshmallow fluff. Add the vanilla extract and salt and beat on medium-high speed for an additional 4 minutes. If the frosting heats up too much during mixing, refrigerate for 5-10 minutes until consistency is thick enough to frost the cake.
- Assemble the cake. Level the cakes if necessary. Set one cake layer, graham cracker side down, on a plate. Cover this layer of cake with ¾ cup of the frosting. Top with a second cake layer and repeat. Place the final layer on top of the cake, face down, and frost the sides and top of the cake. Refrigerate to set the frosting.
- Prepare the chocolate ganache. Microwave the heavy cream on 50% power for 30 second increments or heat on the stovetop in a small saucepan until it just comes to a boil. Place the chopped chocolate and pinch of salt in a glass mixing bowl and pour the cream over the chocolate. Allow this mixture to sit for 2 minutes to melt the chocolate, and then whisk from the center outside until the ganache is smooth. Set aside to cool, whisking occasionally, until the ganache has thickened but is still pourable, 10 to 15 minutes. Transfer the ganache into a piping bag, snip off the corner, and drip the ganache along the edge of the cake, encouraging the ganache to run down the sides. Pour the remaining ganache into the center of the cake.
- Decorate the cake. Add graham crackers along the base of the cake. Place miniature marshmallows around the top of the cake and toast, using a kitchen torch, lighter, or oven broiler. Once marshmallows are toasted, press additional graham cracker squares and pieces of chocolate into the melted marshmallows.
