Mouthwatering S’mores Loaf Cake

Here is my favorite s’mores loaf cake recipe, with a soft chocolate cake base, gooey marshmallow swirls, and a crunchy graham cracker topping that brings all those campfire flavors indoors.

This s’mores loaf cake is what I make when my kids are craving something sweet but it’s too rainy for an actual campfire. I love how it captures all the messy fun of s’mores in a neat slice you can enjoy with your morning coffee.

What Kind of Cocoa Powder Should I Use?

For this s’mores loaf cake, you’ll want to stick with unsweetened dark cocoa powder as called for in the recipe. Dutch-processed cocoa powder works great here since it has a deeper, richer chocolate flavor that pairs perfectly with the graham crackers and marshmallow topping. Natural cocoa powder will also work, but it tends to be a bit more acidic and lighter in color. If you only have regular unsweetened cocoa powder on hand, that’s totally fine too – your cake will still taste amazing. Just make sure whatever cocoa you use is fresh and hasn’t been sitting in your pantry for years, as old cocoa can taste flat and won’t give you that rich chocolate flavor you’re after.

Options for Substitutions

This s’mores loaf cake is pretty forgiving when it comes to swaps, so here are some easy substitutions:

• Sour cream or Greek yogurt: If you don’t have either on hand, you can use regular plain yogurt, buttermilk, or even mayonnaise (trust me on this one!). Each will give you that tender, moist texture you’re looking for.
• Espresso or coffee: No coffee? No worries! You can replace it with the same amount of hot water mixed with 1 teaspoon of vanilla extract, or just use an extra 1/4 cup of milk.
• Unsweetened dark cocoa powder: Regular unsweetened cocoa powder works just fine here. If you only have sweetened cocoa, reduce the sugar by 2 tablespoons to balance things out.
• Graham crackers: You can crush up digestive biscuits, vanilla wafers, or even cinnamon graham crackers for a little extra flavor. Just make sure to break them into similar-sized pieces.
• Whole milk: Any milk you have works – 2%, skim, or even non-dairy alternatives like almond or oat milk. The cake might be slightly less rich with lower-fat options, but it’ll still taste great.
• Semisweet chocolate chips: Feel free to use milk chocolate chips, dark chocolate chips, or even chop up a chocolate bar. Just make sure to melt it completely before adding to the batter.

Watch Out for These Mistakes While Baking

The biggest mistake when making s’mores loaf cake is overmixing the batter once you add the flour, which can lead to a dense, tough cake instead of the tender crumb you’re after – mix just until the ingredients are combined.

Another common error is not letting your melted chocolate cool slightly before adding it to the butter mixture, as hot chocolate can cause the butter to melt and throw off your cake’s texture.

When making the marshmallow topping, make sure your egg whites are at room temperature and your bowl is completely clean and dry, since even a tiny bit of grease or yolk can prevent the whites from whipping properly.

Finally, don’t skip testing for doneness with a toothpick inserted into the center – the cake should have a few moist crumbs clinging to it, but shouldn’t be wet or gooey in the middle.

What to Serve With S’mores Loaf Cake?

This s’mores loaf cake is pretty much perfect on its own, but a scoop of vanilla ice cream alongside each slice makes it feel extra special. I love serving it with a hot cup of coffee or a cold glass of milk – the rich chocolate and graham cracker flavors pair beautifully with both. If you want to go all out, try warming up individual slices for about 10 seconds in the microwave before serving, which makes the chocolate even more gooey and brings out all those campfire vibes. Fresh berries like strawberries or raspberries also make a nice addition if you want something a little tart to balance out the sweetness.

Storage Instructions

Keep Fresh: This s’mores loaf cake stays moist and delicious when wrapped tightly in plastic wrap or stored in an airtight container at room temperature for up to 3 days. The graham cracker topping might soften a bit over time, but it still tastes amazing. If you want to keep it longer, pop it in the fridge for up to a week.

Freeze: You can absolutely freeze this cake for later! Wrap individual slices in plastic wrap and then place them in a freezer bag, or freeze the whole loaf wrapped well for up to 3 months. It’s such a treat to have a slice of s’mores cake ready to go whenever you need a chocolate fix.

Serve: Let frozen slices thaw at room temperature for about 30 minutes before enjoying. If you want to warm it up a bit, just pop a slice in the microwave for 10-15 seconds to get that fresh-baked feel again. The chocolate gets slightly melty and it’s like having s’mores all over again!

Preparation Time	20-30 minutes
Cooking Time	35-40 minutes
Total Time	55-70 minutes
Level of Difficulty	Medium

Estimated Nutrition

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

• Calories: 2200-2400
• Protein: 25-30 g
• Fat: 100-110 g
• Carbohydrates: 300-320 g

Ingredients

For the chocolate cake batter:

• 1/4 cup whole milk
• 1 cup sugar
• 8 tbsp unsalted butter, softened (I use Kerrygold for richness)
• 1 cup plus 1 tbsp all-purpose flour
• 1 shot espresso or 1/4 cup brewed coffee (adds depth without coffee flavor)
• 1/2 tsp kosher salt
• 1 tsp vanilla extract
• 1/3 cup semisweet chocolate chips, melted (use quality chips like Ghirardelli)
• 1/4 cup sour cream
• 1 3/4 tsp baking powder
• 1/3 cup dark unsweetened cocoa powder (finely sifted to remove lumps)
• 2 eggs (room temperature for better mixing)

For the graham cracker layer:

• 5 graham crackers, broken in half (broken into 1-inch pieces)

For the meringue topping:

• 1/2 cup sugar
• 2 egg whites, at room temperature (crucial for stiff peaks)

Step 1: Prepare Equipment and Mise en Place

• 1/3 cup dark unsweetened cocoa powder
• 5 graham crackers
• 1/3 cup semisweet chocolate chips

Preheat your oven to 350°F and prepare a loaf pan by lining it with parchment paper or greasing it lightly.

Sift the cocoa powder through a fine-mesh strainer to remove any lumps—this prevents bitter streaks in your cake.

Break the graham crackers into roughly 1-inch pieces and set aside.

Bring your eggs and egg whites to room temperature (this takes about 30 minutes and ensures better mixing and meringue peaks).

Melt the semisweet chocolate chips gently over a double boiler or in 30-second microwave intervals, stirring between bursts, until completely smooth.

Step 2: Create the Chocolate Cake Batter

• 8 tbsp unsalted butter, softened
• 1 cup sugar
• 2 eggs, room temperature
• 1/3 cup semisweet chocolate chips, melted
• 1/4 cup sour cream
• 1 3/4 tsp baking powder
• 1/2 tsp kosher salt
• 1/3 cup dark unsweetened cocoa powder, sifted
• 1 cup plus 1 tbsp all-purpose flour
• 1/4 cup whole milk
• 1 shot espresso or 1/4 cup brewed coffee
• 1 tsp vanilla extract

Cream together the softened butter and sugar using an electric mixer on medium speed for 2-3 minutes until light and fluffy—this incorporates air for a tender crumb.

Add the room-temperature eggs one at a time, beating well after each addition.

Stir in the melted chocolate and sour cream until just combined.

In a separate bowl, whisk together the baking powder, salt, cocoa powder, and flour.

In another small bowl, combine the milk, espresso, and vanilla extract.

Alternate adding the dry mixture and wet mixture to the chocolate-butter mixture, beginning and ending with the dry ingredients—this prevents overworking the batter and keeps the cake tender.

Step 3: Build the Layered Cake with Graham Crackers

• chocolate cake batter from Step 2
• graham crackers, broken into 1-inch pieces

Spread one-third of the chocolate batter from Step 2 into the prepared loaf pan, smoothing it into an even layer.

Arrange 3 graham cracker halves on top of the batter, pressing them down slightly so they stay embedded.

Repeat this layering process two more times: add another third of batter, then 3 more cracker halves, then the final third of batter with the last 3 cracker halves on top.

I like to slightly stagger the crackers so they peek through when you slice, creating that classic s’mores visual appeal.

Step 4: Bake the Cake

Place the loaf pan in the preheated 350°F oven and bake for 35-40 minutes, until a toothpick inserted into the cake (avoiding the graham crackers) comes out with just a few moist crumbs—don’t overbake or the cake will be dry.

The top should be set but still have a slight dome.

Remove from the oven and let the cake cool in the pan for about 10-15 minutes so it sets slightly and becomes easier to unmold.

Step 5: Prepare the Toasted Marshmallow Meringue

• 2 egg whites, room temperature
• 1/2 cup sugar

While the cake cools, combine the room-temperature egg whites and 1/2 cup sugar in a heatproof bowl.

Place the bowl over a pot of gently simmering water, making sure the bowl doesn’t touch the water.

Whisk constantly for 3-4 minutes until the sugar fully dissolves and the mixture reaches about 160°F (this pasteurizes the egg whites for safety).

Remove from heat and transfer to a stand mixer or use a hand mixer, whipping on medium-high speed for 5-7 minutes until stiff, glossy peaks form.

I always stop just before the peaks look dry—overwhipped meringue becomes grainy and separates.

Step 6: Unmold, Top, and Toast the Cake

• cooled cake from Step 4
• toasted marshmallow meringue from Step 5

Once the cake has cooled slightly, run a thin knife around the edges and invert it onto a serving plate or cutting board.

Spread the meringue from Step 5 generously over the top and sides of the cake, creating rustic peaks and swirls.

Using a kitchen torch, carefully toast the meringue until it’s golden brown with light charring in spots—this mimics the toasted marshmallow experience.

Alternatively, place the cake under a broiler on high heat for 1-2 minutes, watching carefully to avoid burning.

Let cool for 5 minutes before slicing and serving warm.