S'mores Cake
This decadent S'mores Cake features rich chocolate layers, a crispy graham cracker crust, and toasted marshmallow frosting that tastes like a summer campfire.
- Waterproofed Crust: Brushing the par-baked graham crust with egg white creates a hydrophobic barrier, keeping it incredibly crispy.
- Bloomed Cocoa: Mixing hot liquid into the cocoa powder coaxes out deep, complex chocolate notes by releasing trapped volatile flavor compounds.
- Swiss Meringue Stability: Heating egg whites and sugar to 160°F denatures the proteins, creating a marshmallow frosting that holds its shape without weeping.
Three years ago, I tried to toast marshmallows indoors using a wire coat hanger over my gas stove, which immediately filled my tiny apartment with toxic-smelling smoke. My cat bolted under the bed, and my husband had to stand on a chair to fan the smoke detector with a dish towel. It was a spectacular, sticky disaster.
I just wanted that campfire magic.
Most s'mores cakes fail because the graham cracker crust turns into a soggy, sandy mush beneath the heavy batter, while the marshmallow frosting becomes rubbery. When you bake a standard crust under wet batter, the moisture migrates downward, destroying the crisp texture. Furthermore, store-bought marshmallow fluff lacks the structural integrity to hold up between cake layers, sliding out like grease.
The fix is surprisingly simple: we par-bake the graham crust to set the butter-sugar matrix, then brush it with a microscopic layer of egg white to waterproof it. For the cake itself, we bloom the cocoa powder in hot coffee to dissolve the oil-soluble flavor compounds. Finally, we whip up a sturdy Swiss meringue frosting that toasts beautifully under a kitchen torch.
You do not need any fancy bakery equipment to pull this off. Just grab your hand mixer and let's get baking.
If you love deep chocolate flavors, this cake base is a close cousin to our decadent Death by Chocolate Cake. It is intensely moist and holds up beautifully under the fluffy frosting. You will never go back to boxed mixes again.
Bear with me here on the frosting.
While some bakers resort to store-bought fluff, making a real Swiss meringue is hands down the superior route. It clings to the cake like a dream and toasts to a perfect, golden-brown campfire finish. If you want a quicker s'mores fix without turning on the oven, you can always whip up our easy S'mores Dip or these chewy Marshmallow S'mores Bars instead.
But for a showstopping celebration, this layered masterpiece is absolutely worth the extra effort. Trust me on this one.
S'mores Cake
Ingredients
- 1.5 cups (150g) graham cracker crumbs
- 5 tbsp (70g) unsalted butter, melted
- 2 tbsp granulated sugar
- 1 large egg white, lightly beaten (for waterproofing)
- 2 cups (250g) all-purpose flour
- 2 cups (400g) granulated sugar
- 3/4 cup (75g) Dutch-process cocoa powder
- 2 tsp baking powder
- 1.5 tsp baking soda
- 1 tsp Diamond Crystal kosher salt
- 2 large eggs, room temperature
- 1 cup (240ml) whole milk
- 1/2 cup (120ml) vegetable oil
- 1 cup (240ml) hot brewed coffee
- 4 large egg whites (for frosting)
- 1.25 cups (250g) granulated sugar (for frosting)
- 1/2 tsp cream of tartar
- 1 tsp pure vanilla extract
Directions
- Preheat your oven to 350°F (175°C). Grease two 8-inch round cake pans and line the bottoms with parchment paper rounds.
- In a medium bowl, mix the graham cracker crumbs, melted butter, and 2 tablespoons of sugar until it resembles wet sand. Press this mixture firmly into the bottom of the two prepared pans.
- Bake the crusts for 8 minutes until lightly golden. Remove from the oven and immediately brush the warm crusts with a thin layer of the beaten egg white to seal them, then set aside to cool.
- In a large mixing bowl, whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and kosher salt.
- Add the eggs, milk, and vegetable oil to the dry ingredients, beating on medium speed with a hand mixer for about 2 minutes until smooth. Gently stir in the hot coffee by hand (the batter will be very thin).
- Divide the batter evenly between the two pans, pouring it directly over the par-baked graham crusts. Bake for 30 to 35 minutes, or until a toothpick inserted in the center comes out clean. Cool completely.
- For the frosting, combine the 4 egg whites, sugar, and cream of tartar in a heatproof bowl set over a pot of simmering water. Whisk constantly until the sugar completely dissolves and the mixture reaches 160°F (71°C).
- Transfer the warm mixture to a stand mixer fitted with the whisk attachment. Whip on high speed for 7 to 10 minutes until stiff, glossy peaks form and the bowl feels cool, then fold in the vanilla extract.
- Place one cake layer crust-side down on a plate, spread a thick layer of frosting over it, and toast lightly with a kitchen torch. Top with the second layer, cover the top and sides with the remaining frosting, and torch until beautifully caramelized.
Notes
- We highly recommend using Diamond Crystal kosher salt; if you are using Morton's kosher salt or fine sea salt, reduce the amount by half (use 1/2 teaspoon instead of 1 teaspoon) to prevent an overly salty cake.
- Blooming the cocoa powder in hot coffee is essential because the heat dissolves the starch gelatinization and releases the oil-soluble flavor compounds trapped inside the cocoa, resulting in a far deeper chocolate profile.
- When using a kitchen torch to brown the marshmallow frosting, keep the flame moving constantly at a 45-degree angle; holding it in one spot for even two seconds will ignite the sugar and leave a bitter, carbonized taste.
- Because Swiss meringue frosting relies on a delicate protein matrix, it will begin to weep and lose its fluffy volume after 24 hours in the refrigerator, so this cake is best enjoyed the day it is assembled.
- Ensure your mixing bowl and whisk are completely grease-free before whipping the egg whites, as even a microscopic speck of fat will prevent the meringue from reaching stiff peaks.
Serving Suggestions
To truly bring out the campfire nostalgia of this dessert, serve it with elements that contrast its rich, sweet profile. Here are some of our favorite ways to plate and enjoy it:
- A scoop of vanilla bean ice cream to balance the warm, toasted marshmallow notes.
- A drizzle of warm, dark chocolate ganache over each individual slice.
- Extra graham cracker crumbs sprinkled on top for a delightful crunch.
- A side of fresh raspberries or strawberries to cut through the decadent sweetness.
- A hot cup of black coffee or espresso, which complements the bloomed cocoa in the cake.
Storage and Reheating
Store any leftover cake in an airtight container at room temperature for up to two days. Avoid wrapping it tightly with plastic wrap, as the sticky marshmallow frosting will cling to it and peel right off.
Do not freeze the fully assembled cake.
While the chocolate cake layers freeze beautifully on their own, the delicate meringue frosting will collapse and turn watery upon thawing.
If you must refrigerate it, keep in mind that the cold air will eventually cause the sugar in the frosting to weep. Simply slice and serve cold, or let it sit at room temperature for twenty minutes.
Ingredient Substitutes
If you need to adapt this recipe for dietary needs or pantry limitations, here are the best tested swaps:
- Gluten-Free Flour: You can substitute the all-purpose flour with a high-quality 1:1 gluten-free baking blend (like King Arthur or Bob's Red Mill) and use gluten-free graham crackers for the crust.
- Hot Coffee Alternative: If you are sensitive to caffeine, swap the hot brewed coffee for boiling water or a hot chicory herbal blend; the cake will still have excellent texture.
- Vegetable Oil Swap: Any neutral-flavored oil like canola, safflower, or avocado oil works perfectly in place of vegetable oil without altering the flavor.
- Dairy-Free Milk: You can use unsweetened almond milk or oat milk in place of whole milk, though the cake may be slightly less rich due to the lower fat content.
This cake is messy, spectacular, and guaranteed to leave sticky marshmallow smudges on your nose. It is the absolute best kind of baking project to share with people you love. Let me know how your kitchen torching goes in the comments below!
Susan Rosalind
I've been developing recipes for about 12 years, and this one went through the same routine as everything else here: I made it, changed something, made it again, then had someone else cook it from just the written steps to see where it tripped them up. That's the part I care about most – not just that a recipe works for me, but that it works on a Tuesday night in your kitchen too.
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