Is there anything that signals summer and yummy treats better than s’mores? I don’t think so. I mean everyone seems to be extremely annoyed by this “tired” s’mores trend that’s taking over milkshakes, granola bars, donuts, and every other thing you could think of to buy in all corners of food commerce. But I love it! And now that it’s sunny and warm, I can’t stop thinking about s’mores. Something about that combo of the nutty graham cracker, sweet chocolate, and melty marshmallow…it’s addicting.
This cake goes a few steps further and it’s freaking fantastic. The cake actually has graham cracker crumbs in the batter which adds great flavor (in addition to BROWNED BUTTER!) and creates a lovely sponge texture. The filling is a rich chocolate mousse that uses dulce de leche to make it extra delicious. And the piece de resistance? A bourbon vanilla marshmallow fluff that covers the entire cake. And it’s toasted to-boot. Because how could we make a s’mores cake without that characteristic flavor?
But what is that toasted marshmallow flavor? We can thank caramelization for that one! Caramelization is a reaction that breaks down sugar into smaller pieces and creates dark pigments as a byproduct. It occurs at high temperatures—aka hello campfire. Those dark pigments appear as beige then brown and finally black as you break down everything with heat.
The key is to get a toasty brown because the breakdown of sugar by caramelization creates a whole bunch of aromatic compounds as the breakdown products react with one another. Those aromatic compounds are responsible for the nutty sweet flavors you have come to love in things like toasted marshmallows and crème brulee. But caramelization also causes bitter compounds to form as the process continues. The bitter can be a really great thing for rounding out the perfect bite. But if you go too far, that bitterness will be all-encompassing…and your marshmallow will be black. And good luck coming back from that.
So hurrah for caramelization! And can I get a hell yeah for this cake? I think I know what your weekend plans will be…
Adapted from Serious Eats
Graham Cracker Cake
1 ⅛ cups (18 tablespoons) unsalted butter
1 ¼ cups graham crumbs
2 ¼ cups sugar
2 ⅓ cups cake flour
2 ¾ tablespoons baking powder
½ teaspoon salt
1 cup whole milk
⅔ cup buttermilk
10 large egg yolks (reserve the whites for the marshmallow topping)
1 tablespoon vanilla extract
- Preheat the oven to 350⁰F. Prep 3 9-inch cake pans and line them with parchment paper.
- In a medium saucepan, brown the butter. Set aside to cool slightly.
- In a food processor, add the graham crumbs, sugar, cake flour, baking powder, and salt. Pulse to combine, about 20 seconds.
- Whisk together the milk, buttermilk, yolks, and vanilla until smooth. Add to the food processor bowl and process until a batter forms, about 30 seconds. Drizzle in the browned butter (making sure to get all of the milk solids), and process another 30 seconds.
- Divide the batter between the three prepped pans. Bake in the preheated oven until a cake tester comes out clean, about 15-20 minutes.
- When finished baking, remove from the oven and let cool completely. Invert the cakes onto a cooling rack and level (if needed) the cakes to get ready for stacking.
Chocolate Mousse Filling
1-13 oz (369 g) jar Dulce de Leche Sauce
4 large eggs
2 cups heavy cream
1 teaspoon salt
2 ½ cups bittersweet chocolate chips
- Either in a blender or a large bowl with an immersion blender, add the eggs. Set aside.
- In a medium saucepan, add the heavy cream, dulce de leche, and salt and stir to combine. Heat over medium heat continuing to stir until everything comes together. When the mixture comes to a boil, remove from the heat.
- Turn the blender on and drizzle the hot cream mixture into the eggs. Increase the speed to medium. Slowly add the chocolate chips to the blender and puree until fully melted.
- Transfer the mousse to a large dish and refrigerate, uncovered, for at least 4 hours. When cold, cover with plastic wrap and reserve until you are ready to assemble the cake.
- On a cake plate*, begin to assemble the cake. Spread a small dollop of mousse on the surface and put one layer of cake on top. Spread ⅓ of the mousse on top of the layer and level off. Place the second layer of cake on top and spread half of the remaining mousse (another ⅓ of the total) on top. Finally, put the third layer of cake on top and spread the remaining amount of mousse on top of that. Refrigerate until solid, at least one hour.
Bourbon Marshmallow Topping
10 large egg whites, reserved from above
½ teaspoon cream of tartar
½ teaspoon salt
½ cups + 2 tablespoons corn syrup
¼ cup water
1 ½ cups sugar
2 tablespoons bourbon
1 teaspoon vanilla extract
- Mix egg whites, cream of tartar, and salt in low speed in a stand mixer fitted with the paddle attachment. Continue to mix while you move onto the next step.
- Combine the corn syrup, water, and sugar in a medium saucepan. Stir to combine. Heat over medium-high heat. Use a wetted pastry brush to dissolve any sugar crystals on the side of the saucepan. Cook until the syrup is fully combined and is boiling. Put a candy thermometer in the saucepan and continue to heat. You want to heat the syrup to 235⁰F.
- Meanwhile, fit the stand mixer with the whisk attachment. Turn the speed to medium and whip egg whites on medium speed until soft peaks form. You want the egg whites to whip up at the same time as the sugar syrup. Turn either the heat down on the syrup or the speed on the mixer if one is finishing up more quickly than the other.
- When the syrup and egg whites are ready, turn the mixer to low and drizzle the hot syrup into the bowl. Try to aim the syrup on the bottom half of the side of the bowl.
- Increase the speed of the mixer to medium-high and add the bourbon and vanilla to the bowl. Continue to whip the meringue until it cools to room temperature, about 20 minutes.
- Remove the cake from the fridge. Spread the marshmallow topping all over the top and side of cake. Refrigerate for 1 hour to allow topping to set.
- Remove cake from the fridge. Use a kitchen torch to caramelize the marshmallow topping*. Slice and serve immediately.
* Alternatively, if you don’t have a kitchen torch, prep the cake on a sheet pan and broil it in the oven once fully assembled for a couple minutes to caramelize the outside of the cake. When finished, carefully transfer the cake to the cake plate, and serve!