S’mores Layer Cake with Homemade Fluff

Preheat the oven to 350°F (177°C) and grease and line three 6-inch (15.24 cm) cake pans with cooking spray and parchment paper.
Place 1 sleeve of graham crackers in a food processor and turn it on high until there are no more large chunks. In a medium bowl, whisk together the flour, graham cracker crumbs, baking powder, salt, and cinnamon. Set the dry ingredients aside.
In an electric mixer fitted with the whisk attachment, beat the butter, oil, granulated sugar, brown sugar and vanilla extract together, on medium speed, until they’re light and fluffy. This should take 2 to 3 minutes. Then add the eggs, one at time, beating well after each addition. Make sure to scrape the bottom of the bowl as needed.
In five increments, alternate adding the dry ingredients and buttermilk into the batter, beginning and ending with the dry ingredients. Beat the mixture on medium speed, just until the flour is fully incorporated, making sure to scrape the edge of the bowl as needed.
Distribute the batter evenly among the prepared pans and bake for 30-35 minutes, until the cake springs back when it’s poked. Remove the cakes from the pans and allow them to cool completely before frosting.

Begin by thoroughly cleaning the aluminum bowl and the whisk attachment of the stand mixer (they can’t have any fat residue when making meringue). Once they’re clean and dry, place the egg whites and the granulated sugar in the bowl.
In a small saucepan, bring 1/2 cup (118mL) of water to a simmer. Keep the water simmering on low heat and place the bowl with the egg whites and sugar on top of the saucepan, creating a double boiler. Whisk the egg whites and sugar over low heat for 5 to 10 minutes, until the sugar granules are dissolved. You can feel it between your fingers if the sugar is fully dissolved or you can use a candy thermometer and bring the mixture to about 150°F (65°C).
When the sugar granules are fully dissolved in the egg whites, remove the bowl from the heat and place it on the stand mixer fitted with the whisk attachment. Beat the mixture on medium-high speed, until stiff peaks form. Add the vanilla extract and continue beating the mixture until it’s no longer warm. This usually takes about 10-15 minutes. Remove half of the meringue into a separate bowl and set aside.

Place the dark chocolate in a medium bowl and in a small saucepan, heat the heavy cream until it’s simmering. Pour the heavy cream over the chocolate and let it melt for 1-2 minutes. Stir until the chocolate is completely smooth. Set it aside to cool completely.
Place half of the meringue back on the stand mixer and lower the speed to medium. Slowly add in the softened butter, 2 to 3 tablespoons at a time. Once the butter is all incorporated, continue beating on medium speed for a few minutes until it emulsifies into a buttercream (it may go through phases of looking soupy and/or curdled before it emulsifies but it should come together within 5-10 minutes).
Once the buttercream comes together, add in the cocoa powder, salt and only HALF of the melted chocolate.

Place the first layer of cake on a cake board and spread a thin layer of chocolate buttercream on top. Then spread a layer of meringue frosting and a swirl of chocolate ganache (you can reheat the chocolate in the microwave for 5-10 seconds if necessary). Repeat with the second layer and then place the third layer of cake on top.
Smooth out any buttercream that squished out between the layers and refrigerate for at least 60 minutes. Place the rest of the chocolate buttercream on top of the cake and use an offset spatula to work it’s way down the sides. Add in dabs of meringue frosting and chocolate ganache, lightly spreading them in. Top with extra graham cracker crumbs, or even toasted marshmallows if you’re not lazy!