Epic S’mores Cake

The Most Epic Birthday S’mores Cake

If there is one thing I know for sure, it’s that a birthday isn’t just a celebration—it’s an excuse to bake the most over-the-top, decadent thing I can dream up. This year, I went into “ultimate mode” for my husband’s birthday.

He is a die-hard dark chocolate lover, so I knew I couldn’t just do a standard sponge. I decided to lean into those nostalgic, campfire vibes but elevate them with some serious gourmet flair. The result? An Epic S’mores Cake that is—dare I say—the best thing to come out of my kitchen this year.

The Anatomy of the Ultimate S’mores Cake

This isn’t your average “chocolate cake with a few marshmallows on top.” We are talking layers of deep, dark flavor and incredible texture:

• The Black Cocoa Cake: I used black cocoa to give it that “Oreo-adjacent” richness. It’s incredibly moist thanks to the sour cream and a bit of hot brewed coffee, which really makes the chocolate notes sing.
• Toasted Marshmallow Buttercream: Yes, we actually broil real marshmallows until they are gooey and charred, then whip them into a buttercream. It tastes like a summer night in every bite.
• The Crunch Factor: You can’t have a s’more without the graham cracker! I made a “honey-butter graham crunch” that stays crispy inside the layers.
• The Finishing Touches: A silky chocolate ganache and homemade salted caramel sauce.

It’s tall, it’s dramatic, and it’s everything a birthday cake should be. If you want to impress a chocolate lover in your life, this is the one.

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Epic S’mores Cake

Created by Sue Mun

Makes one, very tall, 6″ cake (or a thinner 3 layered 8″ cake)

Ingredients

Black Cocoa Chocolate Cake:

• 340 grams all purpose flour
• 120 grams black cocoa powder
• 20g cornstarch
• 3/4 tsp salt
• 1 1/2 tbsp baking powder
• 525 grams granulated sugar
• 240g vegetable or canola oil
• 3 large eggs, room temperature
• 225 grams sour cream
• 360g hot brewed coffee

Graham Cracker Crunchies:

• 1 1/4 cups (150g) graham cracker crumbs (about 10 full sheet graham crackers)
• 3 tbsp (40g) honey
• 1/3 cup (76g) unsalted butter, melted

Toasted Marshmallow Buttercream Frosting:

• 10 large marshmallows, toasted in the oven until soft and toasted
• 1/2 cup (113g) unsalted butter, room temperature
• 1/2 cup (60g) powdered sugar
• 1/2 tsp vanilla extract
• 4 oz (about half a small jar) Marshmallow Fluff

Chocolate Ganache:

• 9 oz (1 1/2 cups) semi-sweet chocolate chips
• 3/4 cup (180ml) heavy whipping cream

Salted Caramel Sauce:

• 240g sugar
• 95g water
• 115g heavy cream
• 100g butter
• 1 tsp salt 

Instructions:

Make the Salted Caramel Sauce:

1. Cook the water and sugar in a medium sized pot over high heat. Do not stir the sugar at all during this time or else your sugar will crystallize. Cook until the sugar turns into a dark amber color (took about 10-15 minutes. Keep an eye on it!) 
2. Once it is a dark golden amber color, turn off the heat and slowly add in the heavy cream a tablespoon at a time. Use a whisk to stir rapidly while pouring in your cream. 
3. Once all of the cream has been added, add in the butter and salt. 
4. Cook over your stovetop once again until your butter has melted and your caramel is starting to boil. 
5. Strain into a heat safe jar or container. Cool off at room temperature for one hour before storing in the fridge. You can microwave your caramel in 30 second increments until you get the desired consistency for whatever you want to use it for. 

Make the Black Cocoa Chocolate Cake:

1. Preheat the oven to 350F.
2. In a medium bowl, mix together the flour, black cocoa powder, cornstarch, baking powder, and salt. Set aside.
3. In a large mixing bowl, whisk together the eggs, oil, and sugar together until combined.
4. Stir in the sour cream and vanilla extract and whisk until combined.
5. Add in the flour and carefully fold everything together until combined. The batter will be very thick.
6. Carefully pour in the hot coffee into the batter and gently fold the batter to mix everything together. It will look questionable at first but it will come together.
7. Pour the batter into three, greased 8 inch cake pans. Bake for about 35-40 minutes until a toothpick inserted in the middle of the cake, comes out clean with no sticky batter stuck to the toothpick.
8. Cool off completely before assembling.

Make the Chocolate Ganache:

1. In a microwave safe bowl, add in the chocolate chips and heavy cream. Place in the microwave and microwave until melted while stopping to stir every 30 seconds until melted. Set aside in the fridge until ready to use. You can easily warm it back up in the microwave when you are ready to assemble the cake.

Make the Toasted Marshmallow Filling:

1. Set oven to the broil setting. Spread the marshmallows on a baking sheet pan.
2. Throw the marshmallows into the oven until they start to brown, this can take about 2-3 minutes depending on how strong your broiler is. Then take them out once they are browned and let them cool for a few minutes.
3. In a mixing bowl, beat together the butter, powdered sugar, and vanilla until smooth.
4. Add the cooled down marshmallows and the store-bought marshmallow fluff, then beat well until smooth and combined.

Make the Graham Cracker Crunchies:

1. In a small bowl, mix together the graham cracker crumbs, melted butter, and honey until it looks like wet sand and can hold its shape slightly when squeezed together. Place the bowl in the fridge to allow the mixture to harden.

To Assemble:

1. Prep your cake ring onto a silpat or parchment lined sheet pan. Line the sides of the cake ring with acetate or parchment paper. You can use tape to make sure the acetate or parchment paper is taller than the ring itself by 4 inches. 
2. Level out the chocolate cake by cutting off the tops of the domed cake using a serrated cake knife.
3. Place one layer of chocolate cake in the bottom of the cake ring. 
4. Brush with some simple syrup (optional but it prevents your cake from drying out).
5. Scoop about half of the toasted marshmallow frosting in an even layer over the chocolate cake.
6. Sprinkle some graham crumb crunches evenly on top until you can not see any more marshmallow frosting.
7. Dollop a few heaping tablespoons of the chocolate ganache over the graham crunchies and spread in an even layer.
8. Top with a drizzle of salted caramel on top.
9. Place another chocolate cake layer on top.
10. Repeat the same process/order with the filling.
11. Top with the last chocolate cake layer on top.
12. Place the cake in the fridge for about 2 hours or until cold.
13. Unmold the cake and place the cake onto a serving platter or cake stand. Then make a chocolate ganache drip design on the sides if desired with the remaining chocolate ganache is you have any left.
14. Top with some homemade whipped meringue if desired or more store bought marshmallow fluff and toast it using a blow blow torch. 
15. Garnish with some graham crackers, large marshmallows, and some chocolate bars.

Sue Mun