Ultimate S’mores Layer Cake

Here is my favorite s’mores layer cake recipe, with fluffy chocolate cake layers, creamy marshmallow frosting, and a crunchy graham cracker crumb coating that tastes just like the campfire treat.

This s’mores cake is always a hit at birthday parties and family gatherings. I love making it because it brings back memories of summer camping trips, but you get to enjoy it indoors year-round. Plus, no sticky fingers from melted marshmallows!

What Kind of Graham Crackers Should I Use?

For this s’mores layer cake, you’ll want to use regular honey graham crackers – the classic rectangular sheets that come in most grocery stores. Avoid the cinnamon or chocolate varieties since they’ll compete with the other flavors in your cake. Make sure your graham crackers are fresh and crispy, not stale, as they need to crush properly for the crust and maintain some texture for the garnish. You can use any brand you like, but I find that name-brand crackers tend to have a more consistent texture and better flavor than store brands.

Options for Substitutions

This s’mores cake has some room for swaps, though a few ingredients are pretty essential for that classic campfire taste:

• Graham crackers: These are really the star of the s’mores flavor, so I wouldn’t recommend substituting them. However, if you’re in a pinch, you could use digestive biscuits or vanilla wafers, though the taste will be different.
• Buttermilk: No buttermilk? Make your own by adding 1 1/2 tablespoons of lemon juice or white vinegar to regular milk and let it sit for 5 minutes before using.
• Hot coffee: The coffee brings out the chocolate flavor, but you can replace it with hot water or hot milk if you prefer. You could also use decaf coffee if caffeine is a concern.
• Marshmallow fluff: This is pretty key for that s’mores taste, but if you can’t find it, you can make your own by melting mini marshmallows with a little water, or use marshmallow creme.
• Milk chocolate: Feel free to use dark chocolate or semi-sweet chocolate if that’s what you have. You could even mix in some chopped chocolate bars for extra texture.
• Vegetable oil: Canola oil, melted butter, or even applesauce (though this will change the texture slightly) can work as substitutes.

Watch Out for These Mistakes While Baking

The biggest mistake when making s’mores layer cake is adding the hot coffee too quickly to your chocolate batter, which can cause the eggs to scramble – instead, slowly stream in the coffee while mixing on low speed to keep everything smooth. Another common error is not letting your cake layers cool completely before frosting, as warm cake will melt your marshmallow buttercream and create a messy situation. When making the ganache, avoid pouring hot cream directly onto the chocolate all at once, which can cause it to seize – pour it gradually and stir gently from the center outward for a silky finish. Finally, don’t skip chilling the assembled cake for at least an hour before serving, as this helps all the layers set properly and makes slicing much cleaner.

What to Serve With S’mores Layer Cake?

This cake is already pretty indulgent on its own, so I like to keep the sides simple and let it be the star of the show. A scoop of vanilla ice cream is always a good choice – it helps balance out all that rich chocolate and marshmallow sweetness. Cold milk is another classic pairing that works really well, especially if you’re serving this to kids who will definitely want something to wash down all that goodness. For adults, a cup of strong coffee or even hot chocolate can be a fun way to lean into the campfire theme, and the slight bitterness helps cut through the sweetness of the cake.

Storage Instructions

Keep Fresh: This s’mores layer cake is best stored covered at room temperature for up to 3 days. I like to use a cake dome or cover it loosely with plastic wrap to keep the marshmallow frosting from getting too sticky. The graham cracker layers might soften slightly over time, but that’s totally normal!

Refrigerate: If your kitchen is really warm or you need to keep it longer, pop it in the fridge for up to a week. Just bring it back to room temperature about 30 minutes before serving so the frosting gets nice and fluffy again. The chocolate ganache actually tastes amazing when it’s slightly chilled!

Make Ahead: You can definitely prep parts of this cake ahead of time. Bake the chocolate cake layers up to 2 days early and wrap them tightly in plastic wrap. The marshmallow frosting is best made the day you plan to assemble, but the chocolate ganache can be made a day ahead and gently rewarmed before using.

Preparation Time	30-45 minutes
Cooking Time	60-75 minutes
Total Time	90-120 minutes
Level of Difficulty	Medium

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 8000-8500
• Protein: 60-70 g
• Fat: 400-450 g
• Carbohydrates: 900-950 g

Ingredients

For the graham crust:

• 1/2 cup granulated sugar
• 18 full sheets graham crackers (crushed into fine crumbs, about 2 cups)
• 8 tbsp unsalted butter, melted (I use Kerrygold for richness)

For the chocolate cake:

• 1 1/2 tbsp vanilla extract
• 3/4 cup vegetable oil (or any neutral oil)
• 1 1/2 tsp salt
• 1 cup natural unsweetened cocoa powder (freshly sifted for smoother batter)
• 3 large eggs, room temperature (for better emulsification)
• 1 1/2 cups buttermilk
• 3 cups granulated sugar
• 1 1/2 tsp baking powder
• 1 1/2 cups hot coffee (enhances chocolate flavor)
• 1 tbsp baking soda
• 2 3/4 cups all-purpose flour (I use King Arthur)

For the marshmallow frosting:

• 2 tsp vanilla extract
• 10 oz marshmallow fluff (gives it the authentic s’mores taste)
• 1/2 tsp salt
• 1 1/2 cups unsalted butter, softened (room temperature for creamy frosting)
• 7 cups confectioners’ sugar

For the chocolate ganache:

• 7 oz milk chocolate, chopped (finely chopped for even melting)
• 3/4 cup heavy cream (room temperature preferred)
• Pinch salt

For the toppings:

• Miniature marshmallows (toasted lightly for extra flavor, optional)
• Milk chocolate squares
• Additional graham crackers (for decoration and texture)

Step 1: Prepare the Graham Cracker Crust

• 18 full sheets graham crackers
• 8 tbsp unsalted butter, melted
• 1/2 cup granulated sugar

Heat your oven to 350°F (175°C) and grease three 8-inch round cake pans.

Crush the graham crackers into fine crumbs—you should have about 2 cups.

Mix the crumbs with the melted butter and 1/2 cup granulated sugar until the texture resembles wet sand.

Divide the mixture evenly among the prepared pans, pressing gently into an even layer across the bottom.

Bake for 10 minutes until lightly set and fragrant, then remove from the oven and let cool while you prepare the cake batter.

I like using Kerrygold butter here because its richness really comes through in the crust.

Step 2: Mix the Chocolate Cake Batter

• 2 3/4 cups all-purpose flour
• 3 cups granulated sugar
• 1 cup natural unsweetened cocoa powder
• 1 tbsp baking soda
• 1 1/2 tsp baking powder
• 1 1/2 tsp salt
• 3 large eggs, room temperature
• 1 1/2 cups buttermilk
• 1 1/2 cups hot coffee
• 3/4 cup vegetable oil
• 1 1/2 tbsp vanilla extract

In a large bowl, whisk together the flour, 3 cups granulated sugar, freshly sifted cocoa powder, baking soda, baking powder, and salt—sifting the cocoa is important for a smooth, lump-free batter.

In another bowl, combine the room-temperature eggs, buttermilk, hot coffee, vegetable oil, and vanilla extract.

Pour the wet ingredients into the dry ingredients and mix on medium speed for about 2 minutes until just combined and smooth.

I like to use hot coffee here because it intensifies the chocolate flavor without making the cake taste like coffee.

Step 3: Bake the Cake Layers

• chocolate cake batter from Step 2
• prepared graham cracker crusts from Step 1

Divide the chocolate batter from Step 2 evenly among the three pans with cooled graham cracker crusts, pouring it carefully over the baked crust layer.

Bake for 35 minutes, or until a toothpick inserted in the center comes out with just a few moist crumbs.

The cakes should spring back slightly when touched.

Remove from the oven and let cool in the pans for 20 minutes, then turn out onto wire racks to cool completely to room temperature before frosting.

Step 4: Prepare the Marshmallow Frosting

• 1 1/2 cups unsalted butter, softened
• 7 cups confectioners’ sugar
• 10 oz marshmallow fluff
• 2 tsp vanilla extract
• 1/2 tsp salt

Beat the softened butter in a large mixing bowl on medium-high speed for 2-3 minutes until creamy and pale.

Gradually add the confectioners’ sugar, beating well after each addition to avoid lumps.

Once all the sugar is incorporated, add the marshmallow fluff, 2 tsp vanilla extract, and 1/2 tsp salt.

Continue beating for 4 minutes on medium speed until the frosting becomes light, fluffy, and pale—this extra beating incorporates air for a cloud-like texture that’s essential to s’mores cake.

Step 5: Assemble and Frost the Cake

• cooled cake layers from Step 3
• marshmallow frosting from Step 4

Place the first cooled cake layer on your serving plate or cake board.

Spread about 3/4 cup of the marshmallow frosting from Step 4 evenly over the top.

Place the second cake layer on top and repeat with another 3/4 cup frosting.

Top with the third cake layer.

Frost the top and all sides of the cake with the remaining frosting, creating a smooth, even crumb coat.

Refrigerate the frosted cake while you prepare the chocolate ganache.

Step 6: Make the Chocolate Ganache Drip

• 7 oz milk chocolate, chopped finely
• 3/4 cup heavy cream
• Pinch salt

Heat the heavy cream in a small saucepan over medium heat until it just begins to steam—don’t let it boil.

Place the finely chopped milk chocolate and a pinch of salt in a heat-safe bowl.

Pour the hot cream over the chocolate and let it sit undisturbed for 2 minutes to allow the heat to soften the chocolate.

Stir gently with a spatula or whisk until completely smooth and glossy.

Let the ganache cool for 10-15 minutes at room temperature until it reaches a pourable but slightly thick consistency—it should flow slowly rather than run off the cake.

Step 7: Finish with Ganache, Graham Crackers, and Marshmallows

• chocolate ganache from Step 6
• Additional graham crackers
• Miniature marshmallows
• Milk chocolate squares

Remove the chilled cake from the refrigerator.

Pour the chocolate ganache from Step 6 over the top, letting it drip naturally down the sides.

Arrange whole or crushed graham crackers around the base of the cake and on top, pressing them gently into the frosting for texture and visual appeal.

Arrange miniature marshmallows on top of the cake, then use a kitchen torch to lightly toast them until golden and slightly puffy, watching carefully to avoid burning.

If desired, top some marshmallows with small pieces of milk chocolate while they’re still warm so it melts slightly.

Let the cake set for 15 minutes before serving to allow the ganache to firm up.