S'mores Cake Recipe

Moist graham cracker cake layers filled with smooth milk chocolate ganache and coated in a creamy marshmallow buttercream.

Preheat the oven to 350ºF (177ºC). Generously grease and flour (or use homemade cake release) two 8" round cake pans.
In a medium size bowl, toss together the graham cracker crumbs, flour, baking powder, baking soda, and salt. Set aside.
In a large bowl with a handheld mixer or the bowl of a stand mixer fitted with the paddle attachment, cream both sugars and butter until light and fluffy (approximately 3 minutes). Add the eggs one at a time, insuring each egg is completely combined before adding the next, and beat on medium speed until smooth. Add the vanilla, and beat again until combined. Scrape down the sides and bottom of the bowl with a spatula.
Reduce mixer speed to low and slowly add the graham cracker in 2 additions, alternating with the sour cream or yogurt. Beat until completely combined.
Pour the batter evenly between the two prepared cake pans. Bake for 32-36 minutes or until a toothpick inserted in the center comes out mostly clean. Remove from oven and allow cakes to cool in the pans completely on a wire rack before removing and assembling.

Place the chocolate and butter into a medium size bowl. Set aside.
In a small saucepan over medium heat or in the microwave, heat the heavy cream to steam. Remove from heat and immediately pour over the bowl of chocolate and butter.
Allow the mixture to sit for a few minutes, then carefully stir mixture until all of the chocolate is melted. Allow to cool completely at room temperature before using.

In a large bowl with a handheld mixer or the bowl of a stand mixer fitted with the paddle attachment, cream the butter until it is light and fluffy. Add the marshmallow creme and beat on high until smooth (approximately 2 minutes).
With the mixer on low, add the vanilla extract, salt, and powdered sugar. Increase mixer speed to medium and beat until completely combined (approximately 1 minute).

Trim the cooled cake layers to create a flat surface. You can do this with a large serrated knife or a cake leveler. I like to slice each layer in half to make a 4-layer cake, but you can keep it two layers if you prefer.
Place one layer of cake on a cake stand or plate, cut side up. Create a well for the ganache by piping a line of marshmallow buttercream around the edge of the cake layer, then fill the inside of the cake with the ganache. Place another layer of cake on top, cut side down. Repeat until you have used all of the layers.
Create a crumb coat on the cake by coating it in a thin layer of marshmallow buttercream. Refrigerate the cake for about 15-20 minutes to make it sturdy enough to frost with the final layer of marshmallow buttercream.
When your cake is fully coated in buttercream, use an offset spatula to spread the remaining ganache onto the top of the cake, allowing it to drip down the sides, if desired. Before the ganache sets, add additional garnish, if desired.
Once the ganache has set, use a kitchen torch to toast the marshmallows, if desired. Slice and serve once ganache is totally set. Leftovers stay fresh, covered at room temperature up to 3 days and in the refrigerator up to 5 days.
Make ahead: prepare cakes and frosting up to 1 day in advance. Cover cakes tightly and keep at room temperature or in the refrigerator until ready to assemble. Unfrosted cake layers may be frozen, wrapped tightly, up to 2 months.